Compositions and methods for treating type 1 and type 2 diabetes and related disorders

ABSTRACT

The invention features compositions comprising in vitro generated beta cells capable of glucose-stimulated insulin secretion, methods of inducing beta cell maturation from embryonic or induced pluripotent stem cell-derived beta-like cells, and methods of using in vitro generated beta cells for the treatment of type 1 diabetes, type 2 diabetes, or a related disorder.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT/US2015/022799, filed on Mar. 26, 2015, which claims the benefit of and priority to U.S. Provisional Application Nos. 61/971,308, filed Mar. 27, 2014; 62/065,537, filed Oct. 17, 2014; and 62/105,545, filed Jan. 20, 2015, the contents of each of which are incorporated herein by reference.

STATEMENT OF RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH

This invention was made with U.S. government support under DK057978, DK090962, HL088093, HL105278, and ES010337 awarded by the National Institutes of Health. The U.S. government has certain rights in the invention.

SEQUENCE LISTING

The instant application contains a Sequence Listing which has been submitted electronically in ASCII format and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Aug. 3, 2015, is named 365550.1002US1(00018)_SL.txt and is 57,529 bytes in size.

BACKGROUND OF THE INVENTION

Beta cell dysfunction is associated with type 1 and type 2 diabetes. Type 1 diabetes is usually diagnosed in children and young adults and results from autoimmune destruction of insulin-producing pancreatic cells. The defect in insulin production causes a dramatic rise of glucose levels in the blood and urine leading to polyuria (frequent urination), polydipsia (increased thirst), polyphagia (increased hunger), and weight loss. Type 1 diabetes is fatal unless treated with insulin injections, which is therapeutic, but not curative. The generation and production of insulin-secreting cells has long been a major goal in regenerative medicine to cure type 1 and certain types of type 2 diabetes. To date no method exists for the production of fully “functional” cells: that is, in vitro generated cells that can secrete insulin properly in response to physiologic levels of glucose. The production of such cells represents the best hope of curing diabetes. Accordingly, methods for obtaining fully functional beta cells and using such cells for the treatment of diabetes are urgently required.

SUMMARY OF THE INVENTION

As described below, the present invention features compositions comprising in vitro generated beta cells capable of glucose-stimulated insulin secretion, methods of inducing beta cell maturation from embryonic or induced pluripotent stem cell-derived beta-like cells, methods of transplanting these cells in a subject (e.g., human) to restore glucose homeostasis, and methods of using in vitro generated beta cells for the treatment of type 1 diabetes, type 2 diabetes, or a related disorder.

In one aspect, the invention generally provides a method for reprogramming a beta-like cell to a functional beta cell, the method involving expressing recombinant estrogen related receptor (ERR)gamma in a beta-like cell, thereby reprogramming the beta-like cell to a functional beta cell.

In another aspect, the invention provides a method for generating a cell capable of glucose-stimulated insulin secretion, the method involving expressing recombinant estrogen-related receptor (ERR) gamma in a beta-like cell, thereby generating a cell capable of glucose-stimulated insulin secretion.

In yet another aspect, the invention provides a method of ameliorating hyperglycemia in a subject in need thereof, the method involving administering to the subject a beta-like cell expressing recombinant estrogen-related receptor (ERR) gamma, thereby ameliorating hyperglycemia in the subject.

In still another aspect, the invention provides a method of treating type 1 or type 2 diabetes in a subject in need thereof, the method involving administering to the subject a beta-like cell expressing recombinant estrogen-related receptor (ERR) gamma, thereby treating type 1 or type 2 diabetes in the subject.

In another aspect, the invention provides an expression vector containing a beta cell-specific promoter operably linked to a nucleic acid sequence encoding an ERRgamma polypeptide. In one embodiment, the promoter is selected from the group consisting of Insulin, Insulin II, Pdx1, Mafa, Nkx6-1, Pax4 and NeuroD1 promoters. In another embodiment, the expression vector is a viral vector (e.g., a lentiviral vector or adeno associated viral vector (AAV)).

In another aspect, the invention provides a method of ameliorating hyperglycemia in a subject in need thereof, the method involving contacting a beta-like cell with an AAV vector encoding ERRgamma, thereby causing the cell to be capable of glucose-stimulated insulin secretion and administering the cell to the subject, thereby ameliorating hyperglycemia in the subject. In one embodiment, the beta-like cell is derived from the subject or is not derived from the subject.

In another aspect, the invention provides a host cell containing the expression vector of a previous aspect. In one embodiment, the cell is an embryonic stem cell, neonate stem cell, adult stem cell, induced pluripotent stem cell, adipocyte-derived stem cell, human umbilical vein endothelial cell (Huvec), or a progenitor or stem cell thereof.

In another aspect, the invention generally provides a tissue containing the host cell of any previous aspect. In one embodiment, the tissue is a pancreatic tissue.

In another aspect, the invention generally provides an organ containing the host cell of any previous aspect.

In another aspect, the invention generally provides a matrix containing the host cell of any previous aspect.

In another aspect, the invention generally provides a cellular composition containing an effective amount of a host cell of the invention in a pharmaceutically acceptable excipient. In another aspect, the invention generally provides a packaged pharmaceutical containing a host cell of a previous aspect; and instructions for using the cell to ameliorate hyperglycemia in a subject.

In another aspect, the invention generally provides a kit for treating hyperglycemia, the kit containing an effective amount of a host cell of any previous aspect, and instructions for use thereof. In one embodiment, the hyperglycemia is related to type 1 or type 2 diabetes.

In another aspect, the invention generally provides a method for generating a cell capable of glucose-stimulated insulin secretion, the method involving expressing recombinant estrogen-related receptor (ERR) gamma and Pdx1 or ERRgamma, Pdx1, and PGC-1alpha in an human adipose-derived stem cell (hADSC), thereby generating a cell capable of glucose-stimulated insulin secretion. In one embodiment, the invention generally involves expressing Pax4 in the hADSC.

In various embodiments of any of the above aspects or any other aspect of the invention delineated herein, the beta-like cell expresses one or more beta cell transcription factors that is any one or more of Nkx2.2, NeuroD1, Foxa2, Pax6, HNF4a, Pdx1, MafA, and Nkx6-1. In other embodiments of the above aspects, the beta-like cell expresses one or more beta cell markers that is Insulin 1, Insulin 2, glucagon and somatostatin. In other embodiments of the above aspects, the beta-like cell is an embryonic stem cell, induced pluripotent stem cell, adipocyte-derived stem cell, human umbilical vein endothelial cell (Huvec), or a progenitor or stem cell thereof. In other embodiments of the above aspects, the beta-like cell is modified to express ERRgamma in vitro or in vivo. In other embodiments of the above aspects, the beta-like cell is transduced with a viral vector encoding ERRgamma. In other embodiments of the above aspects, the reprogrammed cell expresses insulin. In other embodiments of the above aspects, the reprogrammed cell secretes insulin in response to glucose stimulation. In other embodiments of the above aspects, the beta-like cell is obtained by contacting an embryonic stem cell or induced pluripotent stem cell in culture with one or more of activin A, wingless-type MMTV integration site family member 3A (Wnt3a), insulin growth factor (IGF)-2, extendin (Ex)-4, fibroblast growth factor (FGF)-2, nicotinamide, and/or B27. In other embodiments of the above aspects, the beta-like cell is treated with 50 ng/ml Activin A each day for 1-3, 1-5, or 1-6 days (e.g., 1, 2, 3, 4, 5, or 6 days). In other embodiments of the above aspects, the beta-like cell is treated with 25 ng/ml Wnt3a on day 0. In other embodiments of the above aspects, the beta-like cell is treated with 50 ng/ml IGF-2, Ex-4 50 ng/ml, 10 ng/ml FGF-2, 10 mM nicotinamide, and 1% B27 on day 3. In other embodiments of the above aspects, the obtained beta cell expresses one or more mRNA that is Pdx1, insulin, Mafa, Pax6, NeuroD, GCK, CHGA, VAMP2, PC1/3, Glut2, Nkx6.1, GCG, SST, and U36B4. In other embodiments of the above aspects, the beta-like cells is obtained by expressing in the embryonic stem cell or induced pluripotent stem cell one or more transcription factors that is Oct4, Nanog, Sox17, FoxA2, Pdx1, Nkx6.1, and Ngn3. In other embodiments of the above aspects, the beta cell expresses one or more polypeptides that is insulin, Pdx1, Mafa, Pax6, Glut2, NeuroD1, GCK (glucokinase; hexokinase 4), GCG (glucagon), SST (somatostatin), CHGA (chromogranin A; parathyroid secretory protein 1) and VAMP2 (vesicle-associated membrane protein 2 (synaptobrevin 2)). In still other embodiments of the above aspects, the method reduces blood glucose level in the subject. In other embodiments of the above aspects, the method normalizes blood glucose level in the subject. In other embodiments of the above aspects, the subject is a veterinary or human subject.

The invention provides compositions comprising in vitro generated beta-like cells capable of glucose-stimulated insulin secretion and methods of using such cells for the treatment of subjects having or at risk of developing type 1 or type 2 diabetes or a related metabolic disorder. Other features and advantages of the invention will be apparent from the detailed description, and from the claims.

DEFINITIONS

Unless defined otherwise, all technical and scientific terms used herein have the meaning commonly understood by a person skilled in the art to which this invention belongs. The following references provide one of skill with a general definition of many of the terms used in this invention: Singleton et al., Dictionary of Microbiology and Molecular Biology (2nd ed. 1994); The Cambridge Dictionary of Science and Technology (Walker ed., 1988); The Glossary of Genetics, 5th Ed., R. Rieger et al. (eds.), Springer Verlag (1991); and Hale & Marham, The Harper Collins Dictionary of Biology (1991). As used herein, the following terms have the meanings ascribed to them below, unless specified otherwise.

By “beta-like cell” is meant a cell that expresses at least one pancreatic islet beta cell transcription factor or at least one beta cell marker. Beta-like cells may be derived from embryonic stem cells or induced pluripotent stem cells. If desired, an embryonic stem cell or induced pluripotent stem cell can be induced to become a beta-like cell, for example, by culturing the cell as described herein below, or by recombinantly expressing in the cell (e.g., hADSC) one or more proteins of the invention. (e.g., ERRgamma; ERRgamma and Pdx1; ERRgamma, Pdx1, and PGC-1alpha). If desired, Pax4 is also expressed in combination with ERRgamma; ERRgamma and Pdx1; ERRgamma, Pdx1, and PGC-1 alpha. In one embodiment, a beta-like cell or a descendent thereof expresses insulin and/or is capable of glucose-stimulated insulin secretion.

By “glucose-stimulated insulin secretion” is meant secretes insulin in response to physiologic levels of glucose. A physiological level of glucose would be about 20 mM glucose. By “estrogen-related receptor (ERR) gamma polypeptide” is meant a protein having at least 85% amino acid sequence identity to a human estrogen-related receptor gamma sequence provided at NCBI Ref No. P62508 or a fragment thereof having transcriptional regulatory activity. The sequence of ERRgamma also termed “ERR3” is provided below:

sp|P62508|ERR3_HUMAN Estrogen-related receptor gamma OS = Homo sapiens GN (SEQ ID NO: 1)         10         20         30         40         50         60 MDSVELCLPE SFSLHYEEEL LCRMSNKDRH IDSSCSSFIK TEPSSPASLT DSVNHHSPGG         70         80         90        100        110        120 SSDASGSYSS TMNGHQNGLD SPPLYPSAPI LGGSGPVRKL YDDCSSTIVE DPQTKCEYML        130        140        150        160        170        180 NSMPKRLCLV CGDIASGYHY GVASCEACKA FFKRTIQGNI EYSCPATNEC EITKRRRKSC        190        200        210        220        230        240 QACRFMKCLK VGMLKEGVRL DRVRGGRQKY KRRIDAENSP YLNPQLVQPA KKPYNKIVSH        250        260        270        280        290        300 LLVAEPEKIY AMPDPTVPDS DIKALTTLCD LADRELVVII GWAKHIPGFS TLSLADQMSL        310        320        330        340        350        360 LQSAWMEILI LGVVYRSLSF EDELVYADDY IMDEDQSKLA GLLDLNNAIL QLVKKYKSMK        370        380        390        400        410        420 LEKEEFVTLK AIALANSDSM HIEDVEAVQK LQDVLHEALQ DYEAGQHMED PRRAGKMLMT        430        440        450 LPLLRQTSTK AVQHFYNIKL EGKVPMHKLF LEMLEAKV

By “ERRgamma polynucleotide” is meant any nucleic acid sequence encoding an ERRgamma polypeptide or fragment thereof. An exemplary ERRgamma nucleic acid sequence is provided at NCBI Ref: NM_001438.3:

(SEQ ID NO: 2) aagctccaat cggggcttta agtccttgat taggagagtg tgagagcttt ggtcccaact   61 ggctgtgcct ataggcttgt cactaggaga acatttgtgt taattgcact gtgctctgtc  121 aaggaaactt tgatttatag ctggggtgca caaataatgg ttgccggtcg cacatggatt  181 cggtagaact ttgccttcct gaatcttttt ccctgcacta cgaggaagag cttctctgca  241 gaatgtcaaa caaagatcga cacattgatt ccagctgttc gtccttcatc aagacggaac  301 cttccagccc agcctccctg acggacagcg tcaaccacca cagccctggt ggctcttcag  361 acgccagtgg gagctacagt tcaaccatga atggccatca gaacggactt gactcgccac  421 ctctctaccc ttctgctcct atcctgggag gtagtgggcc tgtcaggaaa ctgtatgatg  481 actgctccag caccattgtt gaagatcccc agaccaagtg tgaatacatg ctcaactcga  541 tgcccaagag actgtgttta gtgtgtggtg acatcgcttc tgggtaccac tatggggtag  601 catcatgtga agcctgcaag gcattcttca agaggacaat tcaaggcaat atagaataca  661 gctgccctgc cacgaatgaa tgtgaaatca caaagcgcag acgtaaatcc tgccaggctt  721 gccgcttcat gaagtgttta aaagtgggca tgctgaaaga aggggtgcgt cttgacagag  781 tacgtggagg tcggcagaag tacaagcgca ggatagatgc ggagaacagc ccatacctga  841 accctcagct ggttcagcca gccaaaaagc catataacaa gattgtctca catttgttgg  901 tggctgaacc ggagaagatc tatgccatgc ctgaccctac tgtccccgac agtgacatca  961 aagccctcac tacactgtgt gacttggccg accgagagtt ggtggttatc attggatggg 1021 cgaagcatat tccaggcttc tccacgctgt ccctggcgga ccagatgagc cttctgcaga 1081 gtgcttggat ggaaattttg atccttggtg tcgtataccg gtctctttcg tttgaggatg 1141 aacttgtcta tgcagacgat tatataatgg acgaagacca gtccaaatta gcaggccttc 1201 ttgatctaaa taatgctatc ctgcagctgg taaagaaata caagagcatg aagctggaaa 1261 aagaagaatt tgtcaccctc aaagctatag ctcttgctaa ttcagactcc atgcacatag 1321 aagatgttga agccgttcag aagcttcagg atgtcttaca tgaagcgctg caggattatg 1381 aagctggcca gcacatggaa gaccctcgtc gagctggcaa gatgctgatg acactgccac 1441 tcctgaggca gacctctacc aaggccgtgc agcatttcta caacatcaaa ctagaaggca 1501 aagtcccaat gcacaaactt tttttggaaa tgttggaggc caaggtctga ctaaaagctc 1561 cctgggcctt cccatccttc atgttgaaaa agggaaaata aacccaagag tgatgtcgaa 1621 gaaacttaga gtttagttaa caacatcaaa aatcaacaga ctgcactgat aatttagcag 1681 caagactatg aagcagcttt cagattcctc cataggttcc tgatgagttt ctttctactt 1741 tctccatcat cttctttcct ctttcttccc acatttctct ttctctttat tttttctcct 1801 tttcttcttt cacctccctt atttctttgc ttctttcatt cctagttccc attctccttt 1861 attttcttcc cgtctgcctg ccttctttct tttctttacc tactctcatt cctctctttt 1921 ctcatccttc cccttttttc taaatttgaa atagctttag tttaaaaaaa aatcctccct 1981 tccccctttc ctttcccttt ctttcctttt tccctttcct tttccctttc ctttcctttc 2041 ctcttgacct tctttccatc tttctttttc ttccttctgc tgctgaactt ttaaaagagg 2101 tctctaactg aagagagatg gaagccagcc ctgccaaagg atggagatcc ataatatgga 2161 tgccagtgaa cttattgtga accatactgt ccccaatgac taaggaatca aagagagaga 2221 accaacgttc ctaaaagtac agtgcaacat atacaaattg actgagtgca gtattagatt 2281 tcatgggagc agcctctaat tagacaactt aagcaacgtt gcatcggctg cttcttatca 2341 ttgcttttcc atctagatca gttacagcca tttgattcct taattgtttt ttcaagtctt 2401 ccaggtattt gttagtttag ctactatgta actttttcag ggaatagttt aagctttatt 2461 cattcatgca atactaaaga gaaataagaa tactgcaatt ttgtgctggc tttgaacaat 2521 tacgaacaat aatgaaggac aaatgaatcc tgaaggaaga tttttaaaaa tgttttgttt 2581 cttcttacaa atggagattt ttttgtacca gctttaccac ttttcagcca tttattaata 2641 tgggaattta acttactcaa gcaatagttg aagggaaggt gcatattatc acggatgcaa 2701 tttatgttgt gtgccagtct ggtcccaaac atcaatttct taacatgagc tccagtttac 2761 ctaaatgttc actgacacaa aggatgagat tacacctaca gtgactctga gtagtcacat 2821 atataagcac tgcacatgag atatagatcc gtagaattgt caggagtgca cctctctact 2881 tgggaggtac aattgccata tgatttctag ctgccatggt ggttaggaat gtgatactgc 2941 ctgtttgcaa agtcacagac cttgcctcag aaggagctgt gagccagtat tcatttaaga 3001 ggcaataagg caaatgccag aattaaaaaa aaaaatcatc aaagacagaa aatgcctgac 3061 caaattctaa aacctaatcc atataagttt attcatttag gaatgttcgt ttaaattaat 3121 ctgcagtttt taccaagagc taagccaata tatgtgcttt tcaaccagta ttgtcacagc 3181 atgaaagtca agtcaggttc cagactgtta agaggtgtaa tctaatgaag aaatcaatta 3241 gatgccccga aatctacagt cgctgaataa ccaataaaca gtaacctcca tcaaatgcta 3301 taccaatgga ccagtgttag tagctgctcc ctgtattatg tgaacagtct tattctatgt 3361 acacagatgt aattaaaatt gtaatcctaa caaacaaaag aaatgtagtt cagcttttca 3421 atgtttcatg tttgctgtgc ttttctgaat tttatgttgc attcaaagac tgttgtcttg 3481 ttcttgtggt gtttggattc ttgtggtgtg tgcttttaga cacagggtag aattagagac 3541 aatattggat gtacaattcc tcaggagact acagtagtat attctattcc ttaccagtaa 3601 taaggttctt cctaataata attaagagat tgaaactcca aacaagtatt cattatgaac 3661 agatacacat caaaatcata ataatatttt caaaacaagg aataatttct ctaatggttt 3721 attatagaat accaatgtat agcttagaaa taaaactttg aatatttcaa gaatatagat 3781 aagtctaatt tttaaatgct gtatatatgg ctttcactca atcatctctc agatgttgtt 3841 attaactcgc tctgtgttgt tgcaaaactt tttggtgcag attcgtttcc aaaactattg 3901 ctactttgtg tgctttaaac aaaatacctt gggttgatga aacatcaacc cagtgctagg 3961 aatactgtgt atctatcatt agctatatgg gactatattg tagattgtgg tttctcagta 4021 gagaagtgac tgtagtgtga ttctagataa atcatcatta gcaattcatt cagatggtca 4081 ataacttgaa atttatagct gtgataggag ttcagaaatt ggcacatccc tttaaaaata 4141 acaacagaaa atacaactcc tgggaaaaaa ggtgctgatt ctataagatt atttatatat 4201 gtaagtgttt aaaaagatta ttttccagaa agtttgtgca gggtttaagt tgctactatt 4261 caactacact atatataaat aaaatatata caatatatac attgttttca ctgtatcaca 4321 ttaaagtact tgggcttcag aagtaagagc caaccaactg aaaacctgag atggagatat 4381 gttcaaagaa tgagatacaa ttttttagtt ttcagtttaa gtaactctca gcattacaaa 4441 agagtaagta tctcacaaat aggaaataaa actaaaacgt ggatttaaaa agaactgcac 4501 gggctttagg gtaaatgctc atcttaaacc tcactagagg gaagtcttct caagtttcaa 4561 gcaagaccat ttacttaatg tgaagttttg gaaagttata aaggtgtatg ttttagccat 4621 atgattttaa ttttaatttt gcttctttta ggttcgttct tatttaaagc aatatgattg 4681 tgtgactcct tgtagttaca cttgtgtttc aatcagatca gattgttgta tttattccac 4741 tattttgcat ttaaatgata acataaaaga tataaaaaat ttaaaactgc tatttttctt 4801 atagaagaga aaatgggtgt tggtgattgt attttaatta tttaagcgtc tctgtttacc 4861 tgcctaggaa aacattttat ggcagtctta tgtgcaaaga tcgtaaaagg acaaaaaatt 4921 taaactgctt ataataatcc aggagttgca ttatagccag tagtaaaaat aataataata 4981 ataataaaac catgtctata gctgtagatg ggcttcacat ctgtaaagca atcaattgta 5041 tatttttgtg atgtgtacca tactgtgtgc tccagcaaat gtccatttgt gtaaatgtat 5101 ttattttata ttgtatatat tgttaaatgc aaaaaggaga tatgattctg taactccaat 5161 cagttcagat gtgtaactca aattattatg cctttcagga tgatggtaga gcaatattaa 5221 acaagcttcc acttttgact gctaaaaaaa aaaaaaaaaa

By “Pancreatic and Duodenal Homeobox-1 (Pdx-1) polypeptide” is meant a protein or fragment thereof having at least 85% homology to the sequence provided at NCBI Reference Sequence: NP_000200.1 and having DNA binding or transcriptional regulation activity. An exemplary human PDX1 amino acid sequence is provided below:

(SEQ ID NO: 3) mngeeqyyaa tqlykdpcaf qrgpapefsa sppaclymgr qpppppphpf pgalgaleqg  61 sppdispyev ppladdpava hlhhhlpaql alphppagpf pegaepgvle epnrvqlpfp 121 wmkstkahaw kgqwaggaya aepeenkrtr taytraqlle lekeflfnky isrprrvela 181 vmlniterhi kiwfqnrrmk wkkeedkkrg ggtavggggv aepeqdcavt sgeellalpp 241 ppppggavpp aapvaaregr lppglsaspq pssvaprrpq epr

By “Pancreatic and Duodenal Homeobox-1 (Pdx-1)” nucleic acid sequence is meant a nucleic acid sequence encoding a PDX-1 polypeptide. Exemplary pdx-1 nucleic acid sequences include NM_000209:

(SEQ ID NO: 4) gggtggcgcc gggagtggga acgccacaca gtgccaaatc cccggctcca gctcccgact   61 cccggctccc ggctcccggc tcccggtgcc caatcccggg ccgcagccat gaacggcgag  121 gagcagtact acgcggccac gcagctttac aaggacccat gcgcgttcca gcgaggcccg  181 gcgccggagt tcagcgccag cccccctgcg tgcctgtaca tgggccgcca gcccccgccg  241 ccgccgccgc acccgttccc tggcgccctg ggcgcgctgg agcagggcag ccccccggac  301 atctccccgt acgaggtgcc ccccctcgcc gacgaccccg cggtggcgca ccttcaccac  361 cacctcccgg ctcagctcgc gctcccccac ccgcccgccg ggcccttccc ggagggagcc  421 gagccgggcg tcctggagga gcccaaccgc gtccagctgc ctttcccatg gatgaagtct  481 accaaagctc acgcgtggaa aggccagtgg gcaggcggcg cctacgctgc ggagccggag  541 gagaacaagc ggacgcgcac ggcctacacg cgcgcacagc tgctagagct ggagaaggag  601 ttcctattca acaagtacat ctcacggccg cgccgggtgg agctggctgt catgttgaac  661 ttgaccgaga gacacatcaa gatctggttc caaaaccgcc gcatgaagtg gaaaaaggag  721 gaggacaaga agcgcggcgg cgggacagct gtcgggggtg gcggggtcgc ggagcctgag  781 caggactgcg ccgtgacctc cggcgaggag cttctggcgc tgccgccgcc gccgcccccc  841 ggaggtgctg tgccgcccgc tgcccccgtt gccgcccgag agggccgcct gccgcctggc  901 cttagcgcgt cgccacagcc ctccagcgtc gcgcctcggc ggccgcagga accacgatga  961 gaggcaggag ctgctcctgg ctgaggggct tcaaccactc gccgaggagg agcagagggc 1021 ctaggaggac cccgggcgtg gaccacccgc cctggcagtt gaatggggcg gcaattgcgg 1081 ggcccacctt agaccgaagg ggaaaacccg ctctctcagg cgcatgtgcc agttggggcc 1141 ccgcgggtag atgccggcag gccttccgga agaaaaagag ccattggttt ttgtagtatt 1201 ggggccctct tttagtgata ctggattggc gttgtttgtg gctgttgcgc acatccctgc 1261 cctcctacag cactccacct tgggacctgt ttagagaagc cggctcttca aagacaatgg 1321 aaactgtacc atacacattg gaaggctccc taacacacac agcggggaag ctgggccgag 1381 taccttaatc tgccataaag ccattcttac tcgggcgacc cctttaagtt tagaaataat 1441 tgaaaggaaa tgtttgagtt ttcaaagatc ccgtgaaatt gatgccagtg gaatacagtg 1501 agtcctcctc ttcctcctcc tcctcttccc cctccccttc ctcctcctcc tcttcttttc 1561 cctcctcttc ctcttcctcc tgctctcctt tcctccccct cctcttttcc ctcctcttcc 1621 tcttcctcct gctctccttt cctccccctc ctctttctcc tcctcctcct cttcttcccc 1681 ctcctctccc tcctcctctt cttccccctc ctctccctcc tcctcttctt ctccctcctc 1741 ttcctcttcc tcctcttcca cgtgctctcc tttcctcccc ctcctcttgc tccccttctt 1801 ccccgtcctc ttcctcctcc tcctcttctt ctccctcctc ttcctcctcc tctttcttcc 1861 tgacctcttt ctttctcctc ctcctccttc tacctcccct tctcatccct cctcttcctc 1921 ttctctagct gcacacttca ctactgcaca tcttataact tgcacccctt tcttctgagg 1981 aagagaacat cttgcaaggc agggcgagca gcggcagggc tggcttagga gcagtgcaag 2041 agtccctgtg ctccagttcc acactgctgg cagggaaggc aaggggggac gggcctggat 2101 ctgggggtga gggagaaaga tggacccctg ggtgaccact aaaccaaaga tattcggaac 2161 tttctattta ggatgtggac gtaattcctg ttccgaggta gaggctgtgc tgaagacaag 2221 cacagtggcc tggtgcgcct tggaaaccaa caactattca cgagccagta tgaccttcac 2281 atctttagaa attatgaaaa cgtatgtgat tggagggttt ggaaaaccag ttatcttatt 2341 taacatttta aaaattacct aacagttatt tacaaacagg tctgtgcatc ccaggtctgt 2401 cttcttttca aggtctgggc cttgtgctcg ggttatgttt gtgggaaatg cttaataaat 2461 actgataata tgggaagaga tgaaaactga ttctcctcac tttgtttcaa acctttctgg 2521 cagtgggatg attcgaattc acttttaaaa ttaaattagc gtgttttgtt ttg

By “Pax4 polypeptide” is meant a protein or fragment thereof having at least 85% homology to the sequence provided at GenBank Accession No. AAI07151 and having DNA binding or transcriptional regulation activity.

(SEQ ID NO: 5) mawsskswlc liasscprdt llpsahhasp vpashltqvs ngcvskilgr yyrtgvlepk  61 giggskprla tppvvariaq lkgecpalfa weiqrqlcae glctqdktps vssinrvlra 121 lqedqglpct rlrspavlap avltphsgse tprgthpgtg hrnrtifsps qaealekefq 181 rgqypdsvar gklatatslp edtvrvwfsn rrakwrrqek lkwemqlpga sqgltvprva 241 pgiisaqqsp gsvptaalpa leplgpscyq lcwataperc lsdtppkacl kpcwghlppq 301 pnsldsgllc lpcpsshcpl aslsgsqall wpgcpllygl e

By “Pax4 nucleic acid molecule” is meant a polynucleotide or fragment thereof that encodes a Pax4 polypeptide. Exemplary Pax4 polypeptides include BC107150, which sequence is provided below:

(SEQ ID NO: 6) gggcagcaag gatgcagtct cccaggagag gatgcactcg gtggtgggaa gccaggctgg   61 aggggcctga gtgaccctct ccacaggcgg gcagggcagt gggagaggtg gtgtgtggat  121 acctctgtct cacgcccagg gatcagcagc atgaaccagc ttggggggct ctttgtgaat  181 ggccggcccc tgcctctgga tacccggcag cagattgtgc ggctagcagt cagtggaatg  241 cggccctgtg acatctcacg gatccttaag gtaatgggcc agcaccttta cccagtgatg  301 gggacaggaa gcagggagaa agggctcctc tgaaggcaag agcctggggc tgttgcaggc  361 tctgagggct tctgggactt gggtcacttc ctgggagatc ctctcggagg ttgaaaaggg  421 gagcctcagg ccctcaaagc tgaggctgga ctcccgactt catggcctgg tccagtaagt  481 cttggctttg tcttatagcc tcctcctgtc ccagggacac tctccttcct tctgcccatc  541 atgcctcacc tgtccctgct tctcacctga ctcaggtatc taatggctgt gtgagcaaga  601 tcctagggcg ttactaccgc acaggtgtct tggagccaaa gggcattggg ggaagcaagc  661 cacggctggc tacaccccct gtggtggctc gaattgccca gctgaagggt gagtgtccag  721 ccctctttgc ctgggaaatc caacgccagc tttgtgctga agggctttgc acccaggaca  781 agactcccag tgtctcctcc atcaaccgag tcctgcgggc attacaggag gaccagggac  841 taccgtgcac acggctcagg tcaccagctg ttttggctcc agctgtcctc actccccata  901 gtggctctga gactccccgg ggtacccacc cagggaccgg ccaccggaat cggactatct  961 tctccccaag ccaagcagag gcactggaga aagagttcca gcgtgggcag tatcctgatt 1021 cagtggcccg tggaaagctg gctactgcca cctctctgcc tgaggacacg gtgagggtct 1081 ggttttccaa cagaagagcc aaatggcgtc ggcaagagaa gctcaagtgg gaaatgcagc 1141 tgccaggtgc ttcccagggg ctgactgtac caagggttgc cccaggaatc atctctgcac 1201 agcagtcccc tggcagtgtg cccacagcag ccctgcctgc cctggaacca ctgggtccct 1261 cctgctatca gctgtgctgg gcaacagcac cagaaaggtg tctgagtgac accccaccta 1321 aagcctgtct caagccctgc tggggccact tgcccccaca gccgaattcc ctggactcag 1381 gactgctttg ccttccttgc ccttcctccc actgtcccct ggccagtctt agtggctctc 1441 aggccctgct ctggcctggc tgcccactac tgtatggctt ggaatgaggc aggagtggga 1501 aggagatggc atagagaaga tctaatacca tcctgcccat tgtccttacc gtcctgccca 1561 tacagactgt ggctccttcc tccttcctgt gattgctccc tcctgtgtgg acg

By “PGC1 alpha polypeptide” is meant a protein or fragment thereof having at least 85% homology to the sequence provided at NCBI Ref: NP_037393.1 or UniProt Ref: Q9UBK2.” An exemplary amino acid sequence is provided below.

>sp|Q9UBK2|PRGC1_HUMAN Peroxisome proliferator-activated receptor gamma coactivator 1-alpha OS = Homo sapiens GN = PPARGC1A PE = 1 SV = 1 (SEQ ID NO: 7) MAWDMCNQDSESVWSDIECAALVGEDQPLCPDLPELDLSELDVNDLDTDSFLGGLKWCSD QSEIISNQYNNEPSNIFEKIDEENEANLLAVLTE7LDSLPVDEDGLPSFDALTDGDVTTD NEASPSSMPDGTPPPQEAEEPSLLKKLLLAPANTQLSYNECSGLSTQNHANHNHRIRTNP AIVKTENSWSNKAKSICQQQKPQRRPCSELLKYLTTNDDPPHTKPTENRNSSRDKCTSKK KSHTQSQSQHLQAKPTTLSLPLTPESPNDPKGSPFENKTIERTLSVELSGTAGLTPPTTP PHKANQDNPFRASPKLKSSCKTVVPPPSKKPRYSESSGTQGNNSTKKGPEQSELYAQLSK SSVLTGGHEERKTKRPSLRLFGDHDYCQSINSKTEILINISQELQDSRQLENKDVSSDWQ GQICSSTDSDQCYLRETLEASKQVSPCSTRKQLQDQEIRAELNKHFGHPSQAVFDDEADK TGELRDSDFSNEQFSKLPMFINSGLAMDGLFDDSEDESDKLSYPWDGTQSYSLFNVSPSC SSFNSPCRDSVSPPKSLFSQRPQRMRSRSRSFSRHRSCSRSPYSRSRSRSPGSRSSSRSC YYYESSHYRHRTHRNSPLYVRSRSRSPYSRRPRYDSYEEYQHERLKREEYRREYEKRESE RAKQRERQRQKAIEERRVIYVGKIRPDTTRTELRDRFEVFGEIEECTVNLRDDGDSYGFI TYRYTCDAFAALENGYTLRRSNETDFELYFCGRKQFFKSNYADLDSNSDDFDPASTKSKY DSLDFDSLLKEAQRSLRR

By “PGC1 alpha polynucleotide” is meant a nucleic acid molecule encoding a PGC1 alpha polypeptide. An exemplary PGC1 alpha polynucleotide sequence is provided below:

(SEQ ID NO: 8) tagtaagaca ggtgccttca gttcactctc agtaaggggc tggttgcctg catgagtgtg   61 tgctctgtgt cactgtggat tggagttgaa aaagcttgac tggcgtcatt caggagctgg  121 atggcgtggg acatgtgcaa ccaggactct gagtctgtat ggagtgacat cgagtgtgct  181 gctctggttg gtgaagacca gcctctttgc ccagatcttc ctgaacttga tctttctgaa  241 ctagatgtga acgacttgga tacagacagc tttctgggtg gactcaagtg gtgcagtgac  301 caatcagaaa taatatccaa tcagtacaac aatgagcctt caaacatatt tgagaagata  361 gatgaagaga atgaggcaaa cttgctagca gtcctcacag agacactaga cagtctccct  421 gtggatgaag acggattgcc ctcatttgat gcgctgacag atggagacgt gaccactgac  481 aatgaggcta gtccttcctc catgcctgac ggcacccctc caccccagga ggcagaagag  541 ccgtctctac ttaagaagct cttactggca ccagccaaca ctcagctaag ttataatgaa  601 tgcagtggtc tcagtaccca gaaccatgca aatcacaatc acaggatcag aacaaaccct  661 gcaattgtta agactgagaa ttcatggagc aataaagcga agagtatttg tcaacagcaa  721 aagccacaaa gacgtccctg ctcggagctt ctcaaatatc tgaccacaaa cgatgaccct  781 cctcacacca aacccacaga gaacagaaac agcagcagag acaaatgcac ctccaaaaag  841 aagtcccaca cacagtcgca gtcacaacac ttacaagcca aaccaacaac tttatctctt  901 cctctgaccc cagagtcacc aaatgacccc aagggttccc catttgagaa caagactatt  961 gaacgcacct taagtgtgga actctctgga actgcaggcc taactccacc caccactcct 1021 cctcataaag ccaaccaaga taaccctttt agggcttctc caaagctgaa gtcctcttgc 1081 aagactgtgg tgccaccacc atcaaagaag cccaggtaca gtgagtcttc tggtacacaa 1141 ggcaataact ccaccaagaa agggccggag caatccgagt tgtatgcaca actcagcaag 1201 tcctcagtcc tcactggtgg acacgaggaa aggaagacca agcggcccag tctgcggctg 1261 tttggtgacc atgactattg ccagtcaatt aattccaaaa cagaaatact cattaatata 1321 tcacaggagc tccaagactc tagacaacta gaaaataaag atgtctcctc tgattggcag 1381 gggcagattt gttcttccac agattcagac cagtgctacc tgagagagac tttggaggca 1441 agcaagcagg tctctccttg cagcacaaga aaacagctcc aagaccagga aatccgagcc 1501 gagctgaaca agcacttcgg tcatcccagt caagctgttt ttgacgacga agcagacaag 1561 accggtgaac tgagggacag tgatttcagt aatgaacaat tctccaaact acctatgttt 1621 ataaattcag gactagccat ggatggcctg tttgatgaca gcgaagatga aagtgataaa 1681 ctgagctacc cttgggatgg cacgcaatcc tattcattgt tcaatgtgtc tccttcttgt 1741 tcttctttta actctccatg tagagattct gtgtcaccac ccaaatcctt attttctcaa 1801 agaccccaaa ggatgcgctc tcgttcaagg tccttttctc gacacaggtc gtgttcccga 1861 tcaccatatt ccaggtcaag atcaaggtct ccaggcagta gatcctcttc aagatcctgc 1921 tattactatg agtcaagcca ctacagacac cgcacgcacc gaaattctcc cttgtatgtg 1981 agatcacgtt caagatcgcc ctacagccgt cggcccaggt atgacagcta cgaggaatat 2041 cagcacgaga ggctgaagag ggaagaatat cgcagagagt atgagaagcg agagtctgag 2101 agggccaagc aaagggagag gcagaggcag aaggcaattg aagagcgccg tgtgatttat 2161 gtcggtaaaa tcagacctga cacaacacgg acagaactga gggaccgttt tgaagttttt 2221 ggtgaaattg aggagtgcac agtaaatctg cgggatgatg gagacagcta tggtttcatt 2281 acctaccgtt atacctgtga tgcttttgct gctcttgaaa atggatacac tttgcgcagg 2341 tcaaacgaaa ctgactttga gctgtacttt tgtggacgca agcaattttt caagtctaac 2401 tatgcagacc tagattcaaa ctcagatgac tttgaccctg cttccaccaa gagcaagtat 2461 gactctctgg attttgatag tttactgaaa gaagctcaga gaagcttgcg caggtaacat 2521 gttccctagc tgaggatgac agagggatgg cgaatacctc atgggacagc gcgtccttcc 2581 ctaaagacta ttgcaagtca tacttaggaa tttctcctac tttacactct ctgtacaaaa 2641 acaaaacaaa acaacaacaa tacaacaaga acaacaacaa caataacaac aatggtttac 2701 atgaacacag ctgctgaaga ggcaagagac agaatgatat ccagtaagca catgtttatt 2761 catgggtgtc agctttgctt ttcctggagt ctcttggtga tggagtgtgc gtgtgtgcat 2821 gtatgtgtgt gtgtatgtat gtgtgtggtg tgtgtgcttg gtttagggga agtatgtgtg 2881 ggtacatgtg aggactgggg gcacctgacc agaatgcgca agggcaaacc atttcaaatg 2941 gcagcagttc catgaagaca cgcttaaaac ctagaacttc aaaatgttcg tattctattc 3001 aaaaggaaat atatatatat atatatatat atatatatat atatataaat taaaaaggaa 3061 agaaaactaa caaccaacca accaaccaac caaccacaaa ccaccctaaa atgacagccg 3121 ctgatgtctg ggcatcagcc tttgtactct gtttttttaa gaaagtgcag aatcaacttg 3181 aagcaagctt tctctcataa cgtaatgatt atatgacaat cctgaagaaa ccacaggttc 3241 catagaacta atatcctgtc tctctctctc tctctctctc tctctttttt ttttcttttt 3301 ccttttgcca tggaatctgg gtgggagagg atactgcggg caccagaatg ctaaagtttc 3361 ctaacatttt gaagtttctg tagttcatcc ttaatcctga cacccatgta aatgtccaaa 3421 atgttgatct tccactgcaa atttcaaaag ccttgtcaat ggtcaagcgt gcagcttgtt 3481 cagcggttct ttctgaggag cggacaccgg gttacattac taatgagagt tgggtagaac 3541 tctctgagat gtgttcagat agtgtaattg ctacattctc tgatgtagtt aagtatttac 3601 agatgttaaa tggagtattt ttattttatg tatatactat acaacaatgt tcttttttgt 3661 tacagctatg cactgtaaat gcagccttct tttcaaaact gctaaatttt tcttaatcaa 3721 gaatattcaa atgtaattat gaggtgaaac aattattgta cactaacata tttagaagct 3781 gaacttactg cttatatata tttgattgta aaaacaaaaa gacagtgtgt gtgtctgttg 3841 agtgcaacaa gagcaaaatg atgctttccg cacatccatc ccttaggtga gcttcaatct 3901 aagcatcttg tcaagaaata tcctagtccc ctaaaggtat taaccacttc tgcgatattt 3961 ttccacattt tcttgtcgct tgtttttctt tgaagtttta tacactggat ttgttagggg 4021 aatgaaattt tctcatctaa aatttttcta gaagatatca tgattttatg taaagtctct 4081 caatgggtaa ccattaagaa atgtttttat tttctctatc aacagtagtt ttgaaactag 4141 aagtcaaaaa tctttttaaa atgctgtttt gttttaattt ttgtgatttt aatttgatac 4201 aaaatgctga ggtaataatt atagtatgat ttttacaata attaatgtgt gtctgaagac 4261 tatctttgaa gccagtattt ctttcccttg gcagagtatg acgatggtat ttatctgtat 4321 tttttacagt tatgcatcct gtataaatac tgatatttca ttcctttgtt tactaaagag 4381 acatatttat cagttgcaga tagcctattt attataaatt atgagatgat gaaaataata 4441 aagccagtgg aaattttcta cctaggatgc atgacaattg tcaggttgga gtgtaagtgc 4501 ttcatttggg aaattcagct tttgcagaag cagtgtttct acttgcacta gcatggcctc 4561 tgacgtgacc atggtgttgt tcttgatgac attgcttctg ctaaatttaa taaaaacttc 4621 agaaaaacct ccattttgat catcaggatt tcatctgagt gtggagtccc tggaatggaa 4681 ttcagtaaca tttggagtgt gtattcaagt ttctaaattg agattcgatt actgtttggc 4741 tgacatgact tttctggaag acatgataca cctactactc aattgttctt ttcctttctc 4801 tcgcccaaca cgatcttgta agatggattt cacccccagg ccaatgcagc taattttgat 4861 agctgcattc atttatcacc agcatattgt gttctgagtg aatccactgt ttgtcctgtc 4921 ggatgcttgc ttgatttttt ggcttcttat ttctaagtag atagaaagca ataaaaatac 4981 tatgaaatga aagaacttgt tcacaggttc tgcgttacaa cagtaacaca tctttaatcc 5041 gcctaattct tgttgttctg taggttaaat gcaggtattt taactgtgtg aacgccaaac 5101 taaagtttac agtctttctt tctgaatttt gagtatcttc tgttgtagaa taataataaa 5161 aagactatta agagcaataa attattttta agaaatcgag atttagtaaa tcctattatg 5221 tgttcaagga ccacatgtgt tctctatttt gcctttaaat ttttgtgaac caattttaaa 5281 tacattctcc tttttgccct ggattgttga catgagtgga atacttggtt tcttttctta 5341 cttatcaaaa gacagcacta cagatatcat attgaggatt aatttatccc ccctaccccc 5401 agcctgacaa atattgttac catgaagata gttttcctca atggacttca aattgcatct 5461 agaattagtg gagcttttgt atcttctgca gacactgtgg gtagcccatc aaaatgtaag 5521 ctgtgctcct ctcattttta tttttatttt tttgggagag aatatttcaa atgaacacgt 5581 gcaccccatc atcactggag gcaaatttca gcatagatct gtaggatttt tagaagaccg 5641 tgggccattg ccttcatgcc gtggtaagta ccacatctac aattttggta accgaactgg 5701 tgctttagta atgtggattt ttttcttttt taaaagagat gtagcagaat aattcttcca 5761 gtgcaacaaa atcaattttt tgctaaacga ctccgagaac aacagttggg ctgtcaacat 5821 tcaaagcagc agagagggaa ctttgcacta ttggggtatg atgtttgggt cagttgataa 5881 aaggaaacct tttcatgcct ttagatgtga gcttccagta ggtaatgatt atgtgtcctt 5941 tcttgatggc tgtaatgaga acttcaatca ctgtagtcta agacctgatc tatagatgac 6001 ctagaatagc catgtactat aatgtgatga ttctaaattt gtacctatgt gacagacatt 6061 ttcaataatg tgaactgctg atttgatgga gctactttaa gatttgtagg tgaaagtgta 6121 atactgttgg ttgaactatg ctgaagaggg aaagtgagcg attagttgag cccttgccgg 6181 gccttttttc cacctgccaa ttctacatgt attgttgtgg ttttattcat tgtatgaaaa 6241 ttcctgtgat tttttttaaa tgtgcagtac acatcagcct cactgagcta ataaagggaa 6301 acgaatgttt caaatcta

By “exogenous” is meant a nucleic acid molecule or polypeptide that is not endogenously present in the cell. The term “exogenous” would therefore encompass any recombinant nucleic acid molecule or polypeptide expressed in a cell, such as foreign, heterologous, and over-expressed nucleic acid molecules and polypeptides.

By “alteration” is meant a change (increase or decrease) in the expression levels of a gene or polypeptide as detected by standard art known methods such as those described above. As used herein, an alteration includes a 10% change in expression levels, preferably a 25% change, more preferably a 40% change, and most preferably a 50% or greater change in expression levels.

By “analog” is meant a structurally related polypeptide or nucleic acid molecule having the function of a reference polypeptide or nucleic acid molecule.

By “an effective amount” is meant the amount of an agent required to ameliorate the symptoms of a disease relative to an untreated patient. The effective amount of active compound(s) used to practice the present invention for therapeutic treatment of a disease varies depending upon the manner of administration, the age, body weight, and general health of the subject. Ultimately, the attending physician or veterinarian will decide the appropriate amount and dosage regimen. Such amount is referred to as an “effective” amount.

By “fragment” is meant a portion of a polypeptide or nucleic acid molecule. This portion contains, preferably, at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the entire length of the reference nucleic acid molecule or polypeptide. A fragment may contain 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 nucleotides or amino acids.

By “functional beta cell” is meant a beta cell capable of glucose-stimulated insulin secretion.

By “fusion protein” is meant a protein that combines at least two amino acid sequences that are not naturally contiguous.

By “increases or decreases” is meant a positive or negative alteration. Such alterations are by 5%, 10%, 25%, 50%, 75%, 85%, 90% or even by 100% of a reference value.

By “isolated cell” is meant a cell that is separated from the molecular and/or cellular components that naturally accompany the cell.

By “isolated nucleic acid molecule” is meant a nucleic acid (e.g., a DNA) that is free of the genes, which, in the naturally-occurring genome of the organism from which the nucleic acid molecule of the invention is derived, flank the gene. The term therefore includes, for example, a recombinant DNA that is incorporated into a vector; into an autonomously replicating plasmid or virus; or into the genomic DNA of a prokaryote or eukaryote; or that exists as a separate molecule (for example, a cDNA or a genomic or cDNA fragment produced by PCR or restriction endonuclease digestion) independent of other sequences. In addition, the term includes an RNA molecule which is transcribed from a DNA molecule, as well as a recombinant DNA which is part of a hybrid gene encoding additional polypeptide sequence.

By an “isolated polypeptide” is meant a polypeptide of the invention that has been separated from components that naturally accompany it. Typically, the polypeptide is isolated when it is at least 60%, by weight, free from the proteins and naturally-occurring organic molecules with which it is naturally associated. In one embodiment, the preparation is at least 75%, 85%, 90%, 95%, or at least 99%, by weight, a polypeptide of the invention. An isolated polypeptide of the invention may be obtained, for example, by extraction from a natural source, by expression from a recombinant nucleic acid encoding such a polypeptide; or by chemically synthesizing the protein. Purity can be measured by any appropriate method, for example, column chromatography, polyacrylamide gel electrophoresis, or by HPLC analysis.

By “marker” is meant any protein or polynucleotide having an alteration in expression level or activity that is associated with a disease or disorder.

By “matrix” is meant a natural or artificial material in which a cell is embedded. In particular embodiment, the matrix comprises a component of the extracellular matrix (e.g., proteoglycans, heparan sulfate, integrin, chondroitin sulfate, keratan sulfate, hyaluronic acid, collagen, elastin, fibronectin, laminin. In other embodiments, the matrix comprises a supportive cell type (e.g., fibroblast, osteoblast, chondrocyte).

The terms “isolated,” “purified,” or “biologically pure” refer to material (e.g., a cell) that is free to varying degrees from components which normally accompany it as found in its native state. “Isolate” denotes a degree of separation from original source or surroundings. “Purify” denotes a degree of separation that is higher than isolation. A “purified” or “biologically pure” protein is sufficiently free of other materials such that any impurities do not materially affect the biological properties of the protein or cause other adverse consequences. That is, a nucleic acid or peptide of this invention is purified if it is substantially free of cellular material, viral material, or culture medium when produced by recombinant DNA techniques, or chemical precursors or other chemicals when chemically synthesized. Purity and homogeneity are typically determined using analytical chemistry techniques, for example, polyacrylamide gel electrophoresis or high performance liquid chromatography. The term “purified” can denote that a nucleic acid or protein gives rise to essentially one band in an electrophoretic gel. For a protein that can be subjected to modifications, for example, phosphorylation or glycosylation, different modifications may give rise to different isolated proteins, which can be separately purified.

By “naturally occurs” is meant is endogenously expressed in a cell of an organism.

By “negative” is meant that a cell expresses an undetectable level of a marker or a reduced level of marker, such that the cell can be distinguished in a negative selection from a population of unselected cells.

By “obtaining” as in “obtaining the polypeptide” is meant synthesizing, purchasing, or otherwise acquiring the polypeptide.

By “operably linked” is meant that a first polynucleotide is positioned adjacent to a second polynucleotide that directs transcription of the first polynucleotide when appropriate molecules (e.g., transcriptional activator proteins) are bound to the second polynucleotide.

By “polypeptide” is meant any chain of amino acids, regardless of length or post-translational modification.

By “positioned for expression” is meant that the polynucleotide of the invention (e.g., a DNA molecule) is positioned adjacent to a DNA sequence that directs transcription and translation of the sequence (i.e., facilitates the production of, for example, a recombinant polypeptide of the invention, or an RNA molecule).

By “positive” is meant that a cell expresses a detectable level of a marker.

As used herein, “obtaining” as in “obtaining an agent” includes synthesizing, purchasing, or otherwise acquiring the agent.

By “Beta cell transcription factor” is meant any transcription factor expressed in a pancreatic tissue. Exemplary pancreatic transcription factors include, but are not limited to, ERRgamma, Pdx-1, Ngn3, Pax4, NeuroD1, Nkx2.2 (human C075092, AAH75092), Nkx6.1 (human P78426, NM_006168) Is11 (human NM_002202, NP_002193), Pax6 (human NP_000271, BC011953), MafA (v-maf musculoaponeurotic fibrosarcoma oncogene homolog A) (human NP_963883, NM_201589)), and MafB (v-maf musculoaponeurotic fibrosarcoma oncogene homolog B) (human NP_005452, NM_005461).

By “promoter” is meant a polynucleotide sufficient to direct transcription. Exemplary promoters include nucleic acid sequences of lengths 100, 250, 300, 400, 500, 750, 900, 1000, 1250, and 1500 nucleotides that are upstream (e.g., immediately upstream) of the translation start site.

By “reduces” is meant a negative alteration of at least 10%, 25%, 50%, 75%, or 100%.

By “reference” is meant a standard or control condition.

A “reference sequence” is a defined sequence used as a basis for sequence comparison. A reference sequence may be a subset of or the entirety of a specified sequence; for example, a segment of a full-length cDNA or gene sequence, or the complete cDNA or gene sequence. For polypeptides, the length of the reference polypeptide sequence will generally be at least about 16 amino acids, preferably at least about 20 amino acids, more preferably at least about 25 amino acids, and even more preferably about 35 amino acids, about 50 amino acids, or about 100 amino acids. For nucleic acids, the length of the reference nucleic acid sequence will generally be at least about 50 nucleotides, preferably at least about 60 nucleotides, more preferably at least about 75 nucleotides, and even more preferably about 100 nucleotides or about 300 nucleotides or any integer thereabout or therebetween.

By “regenerate” is meant capable of contributing at least one cell to the repair or de novo construction of a tissue or organ.

By “reprogramming” is meant altering a cell such that at least one protein product is produced in the reprogrammed cell that is not produced in the cell prior to reprogramming (or in a corresponding control cell). Typically, the reprogrammed cell has an altered transcriptional or translational profile, such that the reprogrammed cell expresses a set of proteins not expressed in the cell prior to reprogramming (or in a corresponding control cell).

By “substantially identical” is meant a polypeptide or nucleic acid molecule exhibiting at least 50% identity to a reference amino acid sequence (for example, any one of the amino acid sequences described herein) or nucleic acid sequence (for example, any one of the nucleic acid sequences described herein). Preferably, such a sequence is at least 60%, more preferably 80% or 85%, and more preferably 90%, 95% or even 99% identical at the amino acid level or nucleic acid to the sequence used for comparison.

Sequence identity is typically measured using sequence analysis software (for example, Sequence Analysis Software Package of the Genetics Computer Group, University of Wisconsin Biotechnology Center, 1710 University Avenue, Madison, Wis. 53705, BLAST, BESTFIT, GAP, or PILEUP/PRETTYBOX programs). Such software matches identical or similar sequences by assigning degrees of homology to various substitutions, deletions, and/or other modifications. Conservative substitutions typically include substitutions within the following groups: glycine, alanine; valine, isoleucine, leucine; aspartic acid, glutamic acid, asparagine, glutamine; serine, threonine; lysine, arginine; and phenylalanine, tyrosine. In an exemplary approach to determining the degree of identity, a BLAST program may be used, with a probability score between e⁻³ and e⁻¹⁰⁰ indicating a closely related sequence.

By “subject” is meant a mammal, including, but not limited to, a human or non-human mammal, such as a bovine, equine, canine, ovine, or feline.

Ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 50 is understood to include any number, combination of numbers, or sub-range from the group consisting 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50.

As used herein, “treatment” refers to clinical intervention in an attempt to alter the disease course of the individual or cell being treated, and can be performed either for prophylaxis or during the course of clinical pathology. Therapeutic effects of treatment include, without limitation, preventing occurrence or recurrence of disease, alleviation of symptoms, diminishment of any direct or indirect pathological consequences of the disease, preventing metastases, decreasing the rate of disease progression, amelioration or palliation of the disease state, and remission or improved prognosis. By “preventing” a disease or disorder, a treatment can prevent deterioration due to a disorder in an affected or diagnosed subject or a subject suspected of having the disorder, but also a treatment may prevent the onset of the disorder or a symptom of the disorder in a subject at risk for the disorder or suspected of having the disorder.

As used herein, the terms “treat,” treating,” “treatment,” and the like refer to reducing or ameliorating a disorder and/or symptoms associated therewith. It will be appreciated that, although not precluded, treating a disorder or condition does not require that the disorder, condition or symptoms associated therewith be completely eliminated.

Unless specifically stated or obvious from context, as used herein, the term or is understood to be inclusive. Unless specifically stated or obvious from context, as used herein, the terms “a”, “an”, and the are understood to be singular or plural.

Unless specifically stated or obvious from context, as used herein, the term “about” is understood as within a range of normal tolerance in the art, for example within 2 standard deviations of the mean. About can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from context, all numerical values provided herein are modified by the term about.

The recitation of a listing of chemical groups in any definition of a variable herein includes definitions of that variable as any single group or combination of listed groups. The recitation of an embodiment for a variable or aspect herein includes that embodiment as any single embodiment or in combination with any other embodiments or portions thereof.

Any compositions or methods provided herein can be combined with one or more of any of the other compositions and methods provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1F show that islets acquire oxidative features postnatally. FIG. 1A is a graph showing glucose-stimulated insulin secretion from mouse neonatal (<14 days) and adult (>12 weeks) pancreatic islets after sequential perfusion with 3 mM and 20 mM glucose (10 islets per assay, n=6). FIGS. 1B and 1C are heatmaps of transcriptional changes in C57BL/6J islets during postnatal maturation. FIG. 1B shows the Row Z-score of downregulated, and FIG. 1C of upregulated genes. FIG. 1D is a graph depicting relative ERRgamma (ERR) expression in isolated islets measured by qPCR. FIG. 1E shows relative ERRgamma expression in murine heart, liver, white adipose (WAT), whole pancreas and isolated islets (n=4). X-gal staining indicating ERRgamma expression in islets from ERRgamma^(−/−) mice (top panel). FIG. 1F shows relative expression of Ldha and selected mitochondrial metabolic genes during postnatal islet maturation, as measured by qPCR. (n=3, data represent the mean±s.e.m., *p<0.01 Student's unpaired t-test. 2 wks, 2 weeks; 6 wks, 6 weeks; 12 wks, 12 weeks).

FIGS. 2A-2C show transcriptional changes between neonatal and adult islets. FIG. 2A is a heatmap of expression changes in pancreatic lineage genes in islets from 2, 6, and 12 week old C57BL/6J mice. FIG. 2B is a table showing biological pathways enriched in neonatal (2 week old) islets, determined by gene ontology (GO). FIG. 2C is a table showing biological pathways enriched in adult (12 week old) islets, determined by gene ontology (GO).

FIGS. 3A and 3B show that ERRgamma is induced during postnatal beta cell development. FIG. 3A is a bar graph showing relative expression of cell type-specific markers in FACS-sorted cell populations from mouse insulin promoter GFP (MIP-GFP) islets at 2 and 12 weeks (n=3). FIG. 3B is a bar graph showing relative expression of ERRgamma and the proliferative marker PdgfR in FACS-sorted cell populations from mouse insulin promoter GFP (MIP-GFP) islets at 2 and 12 weeks (n=3).

FIGS. 4A-4D show phenotyping of beta cell-specific ERRgamma knockout mice. FIG. 4A is a bar graph showing relative expression of ERRgamma in isolated islets and tissues from ERR^(lox/lox) (WT) and ERR KO mice, measured by qPCR. FIG. 4B is a bar graph depicting developmental changes in body weight of WT, ERR KO, and WT (RIP-Cre) mice. FIG. 4C is a line graph depicting developmental changes in ad lib fed blood glucose levels in male mice. FIG. 4D is a line graph depicting developmental changes in ad lib fed blood glucose levels in female mice.

FIGS. 5A-5K show beta cell-specific ERRgamma deleted mice were glucose intolerant. FIG. 5A is a line graph depicting results of an intra-peritoneal glucose tolerance test (IP-GTT) of ERR^(lox/lox) (WT) and ERR KO mice on normal chow diet (NCD; WT n=8, ERR KO n=6). FIG. 5B is a line graph depicting results of an intra-peritoneal glucose tolerance test (IP-GTT) of ERR^(lox/lox) (WT) and ERR KO mice on high fat diet (HFD; WT n=7, ERR KO n=9). FIG. 5C is a line graph showing results of an intra-peritoneal insulin tolerance test (IP-ITT) of ERR^(lox/lox) (WT) and ERR KO mice on NCD (WT n=4, ERR KO n=5). FIG. 5D is a line graph depicting glucose-stimulated insulin secretion of NCD fed mice (WT n=4, ERR KO n=12). FIG. 5E is a line graph depicting glucose-stimulated insulin secretion of HFD fed mice (4 weeks HFD, WT n=6, ERR KO n=6). FIG. 5F depicts images showing isolated islets from HFD-fed WT (top panel) and ERR KO (bottom panel) mice stained for insulin (green) and glucagon (red). FIG. 5G is a bar graph showing insulin content of isolated islets (WT n=17 and ERR KO n=19). FIG. 5H is a bar graph showing relative ERR and Insulin 2 (Ins2) expression in adenoviral-EGFP (Ad-EGFP) and adenoviral-Cre (Ad-Cre) infected ERR^(lox/lox) islets. FIG. 5I is a bar graph depicting an ex vivo GSIS assay of adenoviral-EGFP (Ad-EGFP) and adenoviral-Cre (Ad-Cre) infected ERR^(lox/lox) islets. FIG. 5J is a line graph showing oxygen consumption (OCR) in adenoviral-EGFP (Ad-EGFP) and adenoviral-Cre (Ad-Cre) infected ERR^(lox/lox) islets. FIG. 5K is a bar graph showing that ERR deletion disrupted insulin secretion in response to nutrients. The graph depicts data for ex vivo insulin secretion from ERR^(lox/lox) (WT) and PERR KO islets in response to nutrients (glucose, leucine and glutamine) and KCl.

FIGS. 6A-6G show that beta cell-specific ERRgamma deletion caused glucose intolerance (extended data relating to FIGS. 5A-5J). FIG. 6A is a line graph showing results of an intra-peritoneal glucose tolerance test (IP-GTT) on ERR^(lox/lox) (WT, n=8), ERR KO (n=6), and RIP-Cre (WT (RIP-Cre), n=3) mice fed a normal chow diet (NCD). FIG. 6B is a line graph showing results of an intra-peritoneal glucose tolerance test (IP-GTT) after 4 weeks on a high fat diet (HFD). FIG. 6C is a line graph depicting an intra-peritoneal insulin tolerance test (IP-ITT) of WT and ERR KO mice fed a normal chow diet (NCD; WT, n=4, ERR KO, n=5) and after 4 weeks on a high fat diet (HFD; WT, n=8, ERR KO, n=8). FIG. 6D depicts a line graph (left panel) and a bar graph (right panel) depicting in vivo glucose-stimulated insulin secretion (GSIS) under normal chow diet (NCD; WT n=4, ERR KO n=12, WT(RIP-Cre), n=5). FIG. 6E depicts a line graph (left panel) and a bar graph (right panel) depicting in vivo glucose-stimulated insulin secretion (GSIS) after 4 weeks high fat diet (HFD; WT n=6, ERR KO n=6, and WT(RIP-Cre), n=6), respectively. Bar graph indicates area under the curve (AUC). FIG. 6F is a graph showing ERRgamma expression in isolated islets from WT and Tamoxifen-induced beta cell-specific ERRgammaKO (ERR KO ER; ERR^(lox/lox)×RIP-creER). FIG. 6G is a line graph showing results of IP-GTT of WT (n=9) and ERR KO ER (n=11) mice after tamoxifen (Tam) treatment. Data are shown as mean s.e.m.

FIGS. 7A-7D show that pancreas-specific ERRgamma deletion caused glucose intolerance. FIG. 7A is a bar graph showing body weights of 16 week old male ERRgamma^(lox/lox) (WT) and pancreatic-specific ERRgammaKO (PERR KO; ERR^(lox/lox)×PDX1-Cre) mice. FIG. 7B is a line graph showing an intra-peritoneal glucose tolerance test (IP-GTT) of 16 week old male WT and PERR KO mice fed a normal chow diet (NCD, n=6-10). Data are mean±s.e.m. *p<0.01 Student's unpaired t-test. FIG. 7C is a bar graph showing body weights of 16 week old female ERR^(lox/lox) (WT) and pancreatic-specific ERRgammaKO (PERR KO; ERR^(lox/lox)×PDX1-Cre) mice. FIG. 7D is a line graph showing results of an intra-peritoneal glucose tolerance test (IP-GTT) of 16 week old female WT and PERR KO mice fed a normal chow diet (NCD, n=6-10). Data are mean±s.e.m. *p<0.01 Student's unpaired t-test.

FIGS. 8A-8F show that HFD-fed ERR KO islets were hypertrophic. FIG. 8A depicts images of immunostaining (insulin, green and glucagon, red) of islets from ERR^(lox/lox) (WT) and ERR KO mice fed a normal chow diet (NCD) or high fat diet (HFD). FIG. 8B depicts images of hematoxylin and eosin (H&E) staining of islets from ERR^(lox/lox) (WT) and ERR KO mice fed a normal chow diet (NCD) or high fat diet (HFD). FIG. 8C is a bar graph showing insulin content of islets from WT and ERR KO mice fed a normal chow diet (NCD). FIG. 8D is a bar graph showing insulin content of islets from WT and ERR KO mice fed a high fat diet (HFD). FIG. 8E is a bar graph showing the average area of islet sizes from FIG. 8D (WT, n=5; ERR KO, n=5). FIG. 8F is a bar graph showing the frequency distribution of islet sizes of FIG. 8D (WT, n=5; ERR KO, n=5). Data are mean±s.e.m. *p<0.01 Student's unpaired t-test.

FIGS. 9A-9D show that ERRgamma affected GSIS and bioenergetics in INS-1 cells. FIG. 9A is a bar graph of relative ERRgamma expression in INS-1 cells transfected with scrambled (Control) or ERRgamma-targeted siRNA. FIG. 9B is a bar graph of glucose stimulated insulin secretion (GSIS) in INS-1 cells transfected with scrambled (Control) or ERRgamma-targeted siRNA. FIG. 9C is a bar graph of cellular ATP levels in INS-1 cells transfected with scrambled (Control) or ERRgamma-targeted siRNA. FIG. 9D is a scatter graph of cellular bioenergetics in INS-1 cells transfected with scrambled (Control) or ERRgamma-targeted siRNA. *p<0.01 Student's unpaired t-test.

FIGS. 10A-10H show that islet ERRgamma knockout disrupted islet functional maturation. FIG. 10A depicts two electron microscopy images showing mitochondrial morphology in beta cells from ERR^(lox/lox) (WT) and ERR KO (ERR^(lox/lox)×RIP-Cre) islets (n=8). FIG. 10B is a bar graph depicting mitochondria number in beta cells from ERR^(lox/lox) (WT) and ERR KO (ERR^(lox/lox)×RIP-Cre) islets (n=8). FIG. 10C is a bar graph depicting mitochondrial volume in beta cells from ERR^(lox/lox) (WT) and ERR KO (ERR^(lox/lox)×RIP-Cre) islets (n=8). FIG. 10D is a table of dysregulated biological function categories in ERR KO islets, identified by Gene Ontology (GO). FIG. 10E depicts two sets of bar graphs showing relative expression of metabolic genes in ERR KO (left panel) and pancreatic ERR KO (ERR^(lox/lox)×PDX1-Cre, PERR KO, right panel) islets, as measured by qPCR. FIG. 10F is a heatmap of gene expression levels (Row Z-score) during functional maturation of islets, compared to ERR KO islets. FIG. 10G is a heatmap of expression changes in selected metabolic and secretion/exocytosis pathway genes in ERR KO islets. FIG. 10H shows altered gene expression in ERR KO islets. FIG. 10H depicts a heatmap of 471 hierarchally-clustered genes whose expression changed (Row Z-score) in ERR KO islets, compared to postnatal developmental changes in WT mice.

FIG. 11 is a schematic of genomic analyses of ERR-deleted beta cells. Transcriptional changes between islets from ERR^(lox/lox) (WT, n=3) and ERR KO (n=3) mice were compared to the changes between WT islets after adenoviral EGFP or Cre infection (n=10).

FIGS. 12A and 12B show that ERRgamma directly regulates postnatal islet maturation. FIG. 12A depicts a schematic of the ERR response element identified in 140 down- and 149 up-regulated genes in ERR KO islets. FIG. 12B is a bar graph depicting a ChIP assay for indicated genes in mouse insulinoma cell line (MIN-6 cells). *p<0.01 Student's unpaired t-test.

FIGS. 13A-13K show that ERRgamma promotes maturation of human iPSC-derived beta-like cells. FIG. 13A is a schematic summarizing a protocol for iPSC-derived beta-like cell generation (ED, endoderm; PP, pancreatic progenitors; i L, iPSC-derived beta-like cells; i eta, ERRgamma expressing iPSC-derived beta-like cells). FIG. 13B is a bar graph showing relative expression of human insulin during iPSC differentiation. FIG. 13C depicts two images of human insulin reporter-driven GFP expression (left panel) and phase contrast image (right panel) of day 22 beta-like (i L) cells. FIG. 13D depicts two bar graphs of intracellular (left) and extracellular (right) c-peptide concentrations of i L cells after adenoviral infection: Ad-EGFP infected, i L^(GFP) cells, open bars, Ad-ERR infected, i eta cells, red bars. FIG. 13E is a scatter graph showing induced c-peptide secretion in iβL cells, i L^(GFP) cells, i eta cells, and human islets. FIG. 13F is a table showing functional annotation of upregulated gene categories in i eta cells identified by Gene Ontology (GO). FIG. 13G depicts two heatmaps of expression changes in known beta cell maker genes (left) and metabolic genes (right) in i L^(GFP) and i eta cells (log 2 ratio relative to undifferentiated iPSC). FIG. 13H depicts two electron microscopy images showing mitochondrial morphology and insulin granules (right panels) in i L^(GFP) and i eta cells. FIG. 13I is a line graph depicting oxidative capacity of i L^(GFP) and i eta cells, as measured by oxygen consumption rate (OCR). FIG. 13J has four line graphs showing that cell marker expression was independent of ERR. The graphs show Nkx6-1 and MafA expression in undifferentiated iPSCs, i L and i eta (ERR expressing) cells. FIG. 13K has 11 scatter graphs showing that ERR induced the expression of metabolic genes. Expression of metabolic genes in i L^(GFP) cells and i eta cells, compared to human islets, as determined by qPCR.

FIG. 14 is a set of bar graphs profiling expression of 14 genes in differentiating human iPSC. Relative expression of the pluripotent marker (Nanog), endoderm marker (SOX17), pancreatic progenitor marker (HNF1), early endocrine marker (SOX9), and endocrine/beta-cell markers (Insulin, PDX1, MAFA, NEUROD, GCK, PAX6, VAMP2, GCG, SST, CHGA) in iPSCs during differentiation into beta-like cells is depicted.

FIGS. 15A-15H depict functional characterization of iPSC-derived beta-like cells. FIG. 15A depicts images of immunohistochemical staining for PDX1, c-peptide and PC1/3 (red, left panels), compared to human insulin reporter GFP expression (green, middle panels) and nuclear staining (DAPI blue, right panels) in iPSC-derived beta-like (i L) cells. FIG. 15B shows human insulin reporter-driven GFP expression (top panels) and phase contrast image (bottom panels) of day 30-like (i L) cells. FIG. 15C is a scatter graph showing percentage of i L cells expressing human insulin reporter-driven GFP, as measured by FACS (n=8). The representative FACS analyses is shown to the right. FIG. 15D has two graphs showing representative FACS analyses of insulin (GFP) and glucagon expression in iPSCs and i L cells. FIG. 15E depicts representative electron microscopy analyses of i L cells (day 22) and mouse primary cells (selected mitochondria and insulin granules are indicated by arrows). FIG. 15F is a bar graph depicting glucose and potassium-stimulated c-peptide secretion from i L cells. FIG. 15G is a bar graph showing relative ERRgamma expression in human islets, beta-like cells with adenoviral EGFP expression (i L^(GFP) cells) and beta-like-cells with adenoviral ERRgamma expression (i eta cells). FIG. 15H is a set of 6 graphs of representative FACS analyses showing increased cell marker expression in i L cells. Co-expression of Insulin (GFP reporter) and Nkx6-1 or MafA in iPSCs and i L cells, as measured by FACS. IgG is shown as a negative control.

FIG. 16 depicts a table (left panel) and a heatmap (right panel) showing pathways down-regulated in i eta cells. The table depicts functional annotation of down-regulated gene categories in i eta cells, identified by Gene Ontology (GO). The heatmap depicts expression changes in selected genes involved in cell cycle.

FIG. 17 is a schematic of cell transplantation experiments.

FIGS. 18A-18E show that i eta cells restored glucose homeostasis in diabetic mice. FIG. 18A is a line graph showing acute effects on ad lib fed blood glucose levels in STZ-induced hyperglycemic NOD-SCID mice after mock transplantation (n=3), transplantation of i eta cells (n=5) and mouse islets (200 islets/mice, n=5). FIG. 18B is a line graph depicting chronic effects on ad lib fed blood glucose levels after mock transplantation (n=3), transplantation of i L^(GFP) cells (n=14/12; 2 mice died at 2 weeks), i eta cells (n=13), mouse islets (200 islets/mice, n=5) and human islets (500 islets/mice, n=2). (n=4) and i eta cell transplantation (n=4) into STZ-NOD-SCID mice. FIG. 18C is a bar graph showing human c-peptide levels before and 15 minutes after a glucose challenge after the indicated transplantation. FIG. 18D depicts 4 line graphs showing oxygen consumption (VO2), carbon dioxide production (VCO₂), Respiratory Exchange Ratio (RER), and ambulatory motion (X-beam breaks) of mock (n=4) and i eta cell transplanted (n=4) STZ-NOD-SCID mice after 60 days. FIG. 18E is a schematic depicting the functional maturation of adult beta and i eta cells.

FIGS. 19A and 19B have graphs showing in vivo transplantation studies. FIG. 19A is a line graph showing ad lib fed blood glucose levels in STZ-induced hyperglycemic NOD-SCID mice after mock transplantation (n=3), transplantation of i L^(GFP) (n=8), i eta cells (n=7) and mouse islets (200 islets/mice, n=5) at 6 days after transplantation. FIG. 19B is a line graph showing ad lib fed blood glucose levels in STZ-induced hyperglycemic NOD-SCID mice after mock transplantation (n=3), transplantation of i L^(GFP) cells (n=14/12; 2 mice died at 2 weeks), i eta cells (n=13), mouse islets (200 islets/mice, n=5) and human islets (n=2, #13 & #14 human islets) for 8 weeks after transplantation.

FIG. 20 is a scatter graph showing diversity of the glucose-lowering effect by i eta cells. The graph shows blood glucose levels of individual mice described in FIG. 19B.

FIG. 21 shows immunohistochemistry (IHC) of kidneys in transplanted mice. FIG. 21 has six images of representative IHC of kidneys 2 months post-transplantation, stained for Insulin (Red) and DAPI (Blue).

LISTING OF TABLES

Table 1. Gene list related to FIGS. 1B and 1C

Table 2. Gene list for pancreatic lineage-specific gene expression in neonatal and adult islets

Table 3. Gene list related to FIGS. 10D-10F

Table 4. List of representative up-regulated and down-regulated pathways in i eta cells

Table 5. Additional information regarding human islets.

Table 6. Primer information (qPCR primers “Primers (Fw)” disclosed as SEQ ID NOS 9-45, respectively, in order of appearance; qPCR primers “Primers (Rv)” disclosed as SEQ ID NOS 46-82, respectively, in order of appearance; ChIP primers “Primers (Fw)” disclosed as SEQ ID NOS 83-84, respectively, in order of appearance; ChIP primers “Primers (Rv)” disclosed as SEQ ID NOS 85-86, respectively, in order of appearance; Genotyping Primers “Primers (Fw)” disclosed as SEQ ID NOS 87-91, respectively, in order of appearance; and Genotyping Primers “Primers (Rv)” disclosed as SEQ ID NOS 92-96, respectively, in order of appearance) Table 7. Stepwise differentiation protocol and small molecule information for insulin-producing cells

DETAILED DESCRIPTION OF THE INVENTION

The invention features compositions comprising in vitro generated beta cells capable of glucose-stimulated insulin secretion, methods of inducing beta cell maturation from embryonic or induced pluripotent stem cell-derived beta-like cells or human adipose-derived stem cells (ADSCs), and methods of using in vitro generated beta cells for the treatment of type 1 diabetes, type 2 diabetes, or a related disorder.

The invention is based, at least in part, on the discovery that the orphan nuclear receptor, estrogen related receptor (ERR) gamma regulates beta cell metabolism and insulin secretion. As reported in greater detail below, expression of ERRgamma and ERRgamma target mitochondrial genes are increased during islet development after birth. Beta cell-specific ERRgamma knockout mice showed impaired glucose tolerance with reduced insulin secretion. Genome-wide transcriptome analysis revealed that ERRgamma deletion disrupted the gene regulatory network involved in energy metabolism, which is enhanced during beta cell maturation.

In addition, human iPSC-derived insulin-positive beta-like cells showed activated insulin promoter activity and insulin gene expression, as well as expression of other beta cell markers, but the cells were not glucose-responsive, and showed little expression of ERRgamma or mitochondrial genes. Forced ERRgamma expression significantly increased glucose-stimulated c-peptide secretion and also increased mitochondrial activity in iPSC-derived beta-cell-like-cells. Importantly, overexpression of ERR in human iPSC-derived-like cells yielded functional, glucose-responsive cells (iPSC-derivedβERR transplantable active cells, i eta cells). Furthermore, transplantation of these i eta cells was able to restore glucose homeostasis in a type 1 diabetic mouse model. These results revealed a significant role for ERRgamma in acquiring glucose-stimulated insulin secretion function, which is associated with beta cell maturation.

Beta Cell Maturation

Juvenile/neonatal human and rodent beta cells have poor glucose-stimulated insulin secretion (GSIS) function. During the course of beta cell maturation, the neonatal cell develops the ability to secrete insulin in response to glucose stimulation. During the course of development, beta cells acquire the ability to robustly secrete insulin in response to glucose. Therefore, beta cells acquire insulin secretion during the functional beta cell maturation period. Fully functional beta cells are long lived and tightly regulate whole body glucose homeostasis by regulating insulin production and secretion in response to nutrition intake (e.g., intake of amino acids, free fatty acids and glucose). Since insulin promotes lipid synthesis and glucose uptake in peripheral tissues, such as liver, skeletal muscle and adipose, it is not surprising that loss of beta cell function leads to both type 1 and type 2 diabetes.

Functional beta cells are considered highly metabolic cells because of their high demand for mitochondrial ATP production to facilitate insulin secretion in response to food intake in the form of glucose, amino acids and fatty acids. Beta cell glucose metabolism has the following special features: (1) glucose transportation is not limiting. This results in the rapid equalization of extracellular and intracellular glucose concentration. This equalization is carried out by Glut-2 in rodents and Glut-1 in Humans; (2) Glycolysis is controlled by glucokinase (GK), a hexokinase isoform with a low affinity for glucose. (3) glucose stimulation of beta cells reveals that glycolysis is tightly correlated with mitochondrial metabolism resulting in the quantitative flux of pyruvate (product made by glycolysis) into mitochondria. This is facilitated by low levels of lactate dehydrogenase (LDH) and monocarboxylate transporter (MCT) resulting in the conversion of glucose carbons to pyruvate, which is primarily used in the citric acid cycle and enhanced oxidative phosphorylation. Thus, glucose-stimulated insulin secretion is associated with increased oxidative ATP production in response to glucose.

Estrogen-Related Receptors

Nuclear Receptors are a specialized family of ligand-dependent transcription factors that play central roles in controlling development, growth and metabolism. They are defined by a conserved zinc-finger DNA binding domain and a C-terminal ligand-binding domain (LBD) that can impart multiple regulatory functions. Estrogen-related receptors are orphan nuclear receptors within the family of nuclear receptors, represented by three paralogs in mammals, ERR (NR3B1, Esrra), ERR (NR3B2, Esrrb) and ERR (NR3B3, Esrrg). Although they have no known natural ligands, ERR plays an essential role in embryonic stem cell maintenance. ERR and ERR are known to regulate metabolic genes involved in processing, such as the oxidative tricarboxylic acid (TCA) pathway, the electron transport complex (ETC), and oxidative phosphorylation (OXPHOS). ERR and ERR are important mitochondrial metabolic regulators. Genetic studies in mice have shown the differential roles of ERR and ERR. Mice having a whole body ERR knockout (ERR KO) have no significant developmental defects, but the mice are lean and resistant to high fat diet-induced obesity. In contrast, mice with whole body ERR knockout (ERR KO) mice have significant developmental defects that are lethal in the first week after birth. These defects are associated with the failure of ERR KO mice to undergo a fetal to postnatal metabolic switch in the heart associated with increased postnatal carbohydrate utilization.

Although it is well known that beta cells have high mitochondrial metabolic activity which allows them to secrete insulin in response to glucose and other forms of nutrition, the transcriptional network that regulates beta cell metabolism and insulin secretion is poorly understood. Furthermore, insulin-producing beta-like-cells derived from human pluripotent stem cells do not secrete insulin in response to glucose. To date, no one has produced glucose responsive beta-like-cells.

As reported in more detail below, the present invention identifies a metabolic regulatory pathway for fetal/neonate to adult beta cell maturation. The expression of ERRgamma and related genes increased during this period. Beta cell-specific ERRgamma deficient (ERR KO) mice exhibited glucose intolerance with reduced glucose-stimulated insulin secretion (GSIS) in Normal Chow Diet (NCD) and High Fat Diet (HFD) conditions. Disrupted regulation of genes involved in the ATP biosynthesis pathway and OxPhos is seen in ERR KO islets. Significantly, ERRgamma overexpression increased ATP production in response to glucose in beta-like-cells and caused beta-like-cells to increase their mitochondrial metabolic activity and to exhibit glucose stimulated insulin secretion, which are two hallmarks of functional beta cells. Beta-like cells were generated from human induced pluripotent stem cells (hiPSC) and directly from human adipose-derived stem cells (hADSC). These results suggest that metabolic maturation through ERRgamma signaling is likely the transcriptional pathway responsible for the metabolic maturation of beta cells. These results provide for the production of functional, glucose responsive human beta cells from hiPSC, hADSC and other stem cells by over-expression of ERRgamma in such cells.

ERR Gamma Overexpression

The invention provides methods for reprogramming a beta-like cell by over-expressing ERR gamma in a beta-like cell and inducing the beta-like cell to become capable of glucose-stimulated insulin secretion. Typically, over-expression of ERRgamma is also associated with increased mitochondrial metabolic activity.

Transducing viral (e.g., retroviral, adenoviral, and adeno-associated viral) vectors can be used to express ERRgamma in a cell, especially because of their high efficiency of infection and stable integration and expression (see, e.g., Cayouette et al., Human Gene Therapy 8:423-430, 1997; Kido et al., Current Eye Research 15:833-844, 1996; Bloomer et al., Journal of Virology 71:6641-6649, 1997; Naldini et al., Science 272:263-267, 1996; and Miyoshi et al., Proc. Natl. Acad. Sci. U.S.A. 94:10319, 1997). For example, a polynucleotide encoding an ERRgamma polypeptide, variant, or fragment thereof, can be cloned into a retroviral vector and expression can be driven from its endogenous promoter, from the retroviral long terminal repeat, or from a promoter specific for a target cell type of interest, such as a pancreatic islet beta cell. Exemplary promoters useful in the methods of the invention include, but are not limited to, the human insulin promoter, insulin II promoter, as well as other promoters such as Pdx1, Mafa, Nkx6-1 Pax4 and NeuroD1 expressed in a pancreatic tissue, such as a islet beta cell.

Other viral vectors that can be used in the methods of the invention include, for example, a vaccinia virus, a bovine papilloma virus, or a herpes virus, such as Epstein-Barr Virus (also see, for example, the vectors of Miller, Human Gene Therapy 15-14, 1990; Friedman, Science 244:1275-1281, 1989; Eglitis et al., BioTechniques 6:608-614, 1988; Tolstoshev et al., Current Opinion in Biotechnology 1:55-61, 1990; Sharp, The Lancet 337:1277-1278, 1991; Cornetta et al., Nucleic Acid Research and Molecular Biology 36:311-322, 1987; Anderson, Science 226:401-409, 1984; Moen, Blood Cells 17:407-416, 1991; Miller et al., Biotechnology 7:980-990, 1989; Le Gal La Salle et al., Science 259:988-990, 1993; and Johnson, Chest 107:77S-83S, 1995). Retroviral vectors are particularly well developed and have been used in clinical settings (Rosenberg et al., N. Engl. J. Med 323:370, 1990; Anderson et al., U.S. Pat. No. 5,399,346). In one embodiment, an adeno-associated viral vector (e.g., serotype 2) is used to administer a polynucleotide to a beta-like cell, including a beta-like cell derived from a pluripotent stem cell, induced pluripotent stem cell, embryonic stem cell or other cell-type capable of giving rise to beta-like cells.

Non-viral approaches can also be employed for the introduction of an ERRgamma polynucleotide into a beta-like cell derived from a pluripotent stem cell, induced pluripotent stem cell, embryonic stem cell or other cell-type capable of giving rise to beta-like cells. For example, a nucleic acid molecule can be introduced into a cell by administering the nucleic acid in the presence of lipofection (Feigner et al., Proc. Natl. Acad. Sci. U.S.A. 84:7413, 1987; Ono et al., Neuroscience Letters 17:259, 1990; Brigham et al., Am. J. Med. Sci. 298:278, 1989; Staubinger et al., Methods in Enzymology 101:512, 1983), asialoorosomucoid-polylysine conjugation (Wu et al., Journal of Biological Chemistry 263:14621, 1988; Wu et al., Journal of Biological Chemistry 264:16985, 1989), or by micro-injection under surgical conditions (Wolff et al., Science 247:1465, 1990). In one embodiment, the nucleic acids are administered in combination with a liposome and protamine.

Gene transfer can also be achieved using non-viral means involving transfection in vitro. Such methods include the use of calcium phosphate, DEAE dextran, electroporation, and protoplast fusion. Liposomes can also be potentially beneficial for delivery of DNA into a cell (e.g., a beta-like cell derived from a pluripotent stem cell, induced pluripotent stem cell, embryonic stem cell or other cell-type capable of giving rise to beta-like cells). Transplantation of an ERRgamma polynucleotide can also be accomplished by transferring a normal nucleic acid into a cultivatable cell type ex vivo (e.g., an autologous or heterologous primary cell or progeny thereof), after which the cell (or its descendants) are injected into a targeted tissue (e.g., pancreatic tissue) or delivered via a canula. Human islets can survive in subcutaneous skin or fat and kidney with or without immune reaction protective devices such as Theracyte (Theracyte Inc, US). Cells can be transplanted using similar methods for human islet transplantation.

cDNA expression for use in polynucleotide therapy methods can be directed from any suitable promoter (e.g., the human cytomegalovirus (CMV), simian virus 40 (SV40), or metallothionein promoters), and regulated by any appropriate mammalian regulatory element. For example, if desired, enhancers known to preferentially direct gene expression in specific cell types (e.g., pancreatic cells, beta cells) can be used to direct the expression of a nucleic acid. The enhancers used can include, without limitation, those that are characterized as tissue- or cell-specific enhancers. Alternatively, if a genomic clone is used as a therapeutic construct, regulation can be mediated by the cognate regulatory sequences or, if desired, by regulatory sequences derived from a heterologous source, including any of the promoters or regulatory elements described above.

Beta-Like Cells

Cells useful in the methods of the invention include virtually any cell type that expresses markers that are typically expressed in a beta cell or beta cell progenitor. In particular embodiments, cells useful in the invention can be induced to acquire glucose-stimulated insulin secretion by over-expression of ERRgamma.

In particular embodiments, cells useful in the invention include, but are not limited to, adult or embryonic stem cells or other multi- or pluripotent stem cells that express or that can be induced to express one or more pancreatic islet beta cell markers, endocrine markers or beta cell transcription factors. Exemplary beta cell transcription factors include Pdx1, Mafa, Math, Nkx6.1, NeuroD1, Foxa2, Hnf4a, Nkx2.2, Pax6 and HNF4a. In particular embodiments, the beta cell transcription factor is a factor expressed at higher levels in an adult islet cell relative to a neonatal islet cell. Beta cell transcription factors expressed at increased levels in an adult islet include Pdx1, MafA and Nkx6-1 compared with neonatal islets. In other embodiments, a beta-like cell expresses a beta cell marker including, but not limited to, Insulin 1, Insulin 2, —cell marker glucagon and—cell marker, somatostatin. In other embodiments, the beta-like cell expresses an endocrine marker including, but not limited to, Insulin1, Insulin2, Glucagon and Somatostatin.

In particular embodiments, human induced pluripotent stem cells are derived from Huvec (iPSC) or from Embryonic stem cells (H9ES). Cells of the invention may be maintained, for example, on matrigel (BD) coated dishes in virtually any culture media that supports growth or maintenance of the cells (e.g., complete TeSR Media). For pancreatic differentiation, hPC are infected with a human insulin reporter lentivirus (pGreenZero lenti reporter human insulin, System biosciences) or using any other standard transfection method.

In one embodiment, pancreatic differentiation is induced by treating the cells with Activin (e.g., 50-100 ng/ml human Activin (Sigma), Wnt3a (e.g, 25 ng/ml recombinant human Wnt3a (Sigma)) in custom TESR (TeSR without FGF2 and TGF) for 2 days and then with Activin (e.g., 100 ng/ml human Activin) in custom TESR for extra 2 days (Stage 1).

Subsequently, the medium was replaced with culture media (e.g., DMEM) supplemented with 2% BSA, 1% NEAA, 1% Glutamax (Base Media) with 1 μM dorsomorphin (Calbiochem), 2 μM Retinoic Acid (Sigma), optionally 50 ng/ml recombinant human FGF10 (R & D systems), and 10 μM SB431542 for 7 days (Stage 2). Then, the media was replaced with base media containing, for example, 10 μM Forskolin (Sigma), 10 μM dexamethasone (Stemgent), 5 μM TGF RI Kinase inhibitor II (Calbiochem), 10 mM Nicotinamide (Sigma) for 10 days (stage 1). Media were replaced every day (stage 1), every day or every other day (stage 2) and every other day (stage 3). These treatment methods result in the production of beta-like cells that may be modified to over-express ERRgamma. In one embodiment, beta-like cells are transduced, for example, with an Adenoviral ERRgamma purchased from Welgen, Inc.

The invention is not limited to beta-like cells produced using such methods, but encompasses virtually any beta-like cell known in the art. Methods for producing beta-like cells are known in the art and described herein, for example, where an embryonic stem cell or induced pluripotent stem cell is recombinantly modified to express any one or more of Oct4, Nanog, Sox17, FoxA2, Pdx1, Nkx6.1, and/or Ngn3. Beta-like cells generated by such methods express one or more of the following markers: insulin, Pdx1, Mafa, Pax6, Glut2, NeuroD1, glucokinase, glucagon, somatostatin, chromogranin A, and Vamp2. See also, Pagliuca et al., Dev. 140:2472-2483, 2013, which is incorporated herein by reference in its entirety.

As reported in detail below, the present studies determined the expression of nuclear receptor (NR) family members and their co-activators during the normal 10-12 week maturation process of fetal glycolytic (non-functional) beta cells to mature oxidative glucose-responsive beta cells. This led to the identification of a number of nuclear receptors whose expression increased during the normal physiological maturation of functional beta cells, including ERRgamma, ERRalpha, FXR, VDR and their co-activators PGC-1alpha and PGC-1beta.

Utilizing this knowledge, combinations of these receptors and co-activators were expressed in combination with Pdx1 (Pancreatic and duodenal homeobox 1, a known master regulatory transcription factor in pancreatic development and beta-cells) in human adipose-derived stem cells (hADSC). This approach led to the development of a novel 2-factor protocol in which forced expression of Pdx1 in concert with ERRgamma facilitated direct reprogramming of hADSC into “functional” glucose-responsive beta cells. Furthermore, a 3-factor protocol, which included expression of PGC-1alpha with Pdx1 and ERRgamma, resulted in increased glucose responsiveness in the hADSC-derived beta cell. Notably, stably enhanced expression of ERRgamma, with Pdx1 in combination with other beta cell maturation genes such as Pax4 also produced functional glucose-responsive beta cells. However, in the absence of ERRgamma, these beta cell maturation gene combinations failed to produce functional glucose-responsive beta cells. Together these results identify ERRgamma as an important competence factor. These findings have potential medicinal and commercial value in being able to produce large amounts of immunologically compatible and functional pancreatic beta cells for the treatment of type 1 and insulin-dependent type 2 diabetes.

ERRgamma Polypeptide Analogs

The invention further includes analogs of any naturally-occurring polypeptide of the invention. Analogs can differ from a naturally-occurring polypeptide of the invention by amino acid sequence differences, by post-translational modifications, or by both. Analogs of the invention will generally exhibit at least 85%, more preferably 90%, and most preferably 95% or even 99% identity with all or part of a naturally-occurring ERRgamma amino acid sequence of the invention. The length of sequence comparison is at least 5, 10, 15 or 20 amino acid residues, preferably at least 25, 50, or 75 amino acid residues, and more preferably more than 100 amino acid residues. Again, in an exemplary approach to determining the degree of identity, a BLAST program may be used, with a probability score between e⁻³ and e⁻¹⁰⁰ indicating a closely related sequence. Modifications include in vivo and in vitro chemical derivatization of polypeptides, e.g., acetylation, carboxylation, phosphorylation, or glycosylation; such modifications may occur during polypeptide synthesis or processing or following treatment with isolated modifying enzymes. Analogs can also differ from the naturally-occurring polypeptides of the invention by alterations in primary sequence. These include genetic variants, both natural and induced (for example, resulting from random mutagenesis by irradiation or exposure to ethanemethylsulfate or by site-specific mutagenesis as described in Sambrook, Fritsch and Maniatis, Molecular Cloning: A Laboratory Manual (2d ed.), CSH Press, 1989, or Ausubel et al., supra). Also included are cyclized peptides, molecules, and analogs which contain residues other than L-amino acids, e.g., D-amino acids or non-naturally occurring or synthetic amino acids, e.g., .beta. or .gamma. amino acids.

In addition to full-length polypeptides, the invention also provides fragments of any one of the polypeptides or peptide domains of the invention. As used herein, the term “a fragment” means at least 5, 10, 13, or 15 amino acids. In other embodiments a fragment is at least 20 contiguous amino acids, at least 30 contiguous amino acids, or at least 50 contiguous amino acids, and in other embodiments at least 60 to 80, 100, 200, 300 or more contiguous amino acids. Fragments of the invention can be generated by methods known to those skilled in the art or may result from normal protein processing (e.g., removal of amino acids from the nascent polypeptide that are not required for biological activity or removal of amino acids by alternative mRNA splicing or alternative protein processing events).

Methods of analog design are well known in the art, and synthesis of analogs can be carried out according to such methods by modifying the chemical structures such that the resultant analogs increase the reprogramming or regenerative activity of a reference ERRgamma polypeptide. These chemical modifications include, but are not limited to, substituting alternative R groups and varying the degree of saturation at specific carbon atoms of a reference fusion polypeptide. Preferably, the ERRgamma protein analogs are relatively resistant to in vivo degradation, resulting in a more prolonged therapeutic effect upon administration. Assays for measuring functional activity include, but are not limited to, those described in the Examples below.

Therapeutic Methods

The invention provides for the treatment of type 1 diabetes, type 2 diabetes, pre-diabetes, and the treatment of other metabolic diseases or disorders associated with a deficiency in beta cell number (e.g., a reduction in the number of pancreatic cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose-stimulated insulin secretion, a deficiency in insulin production). For example, the invention provides compositions for the treatment of diabetic patients who lack sufficient levels of insulin due to a decrease in the number or activity of insulin-producing pancreatic cells. Many diseases associated with a deficiency in cell number are characterized by beta cell loss or an increase in beta cell death. Methods of the invention ameliorate such type 1 diabetes, type 2 diabetes, and related diseases, disorders, by generating cells (e.g., insulin-expressing cells) that can supplement the deficiency. Such cells are generated from the reprogramming of a cell to a cell type of interest (e.g., the reprogramming of a beta-like cell, embryonic stem cell, induced pluripotent cell) or by promoting the regeneration of a beta cell, pancreatic tissue, or organ. In general, the invention provides a method for reprogramming a cell that involves contacting the cell (e.g., a beta-like cell, such as derived from an induced pluripotent stem cell, or stem cell derived from adipocytes, endothelial cells, pancreatic cells, and their progenitor cells or stem cells) with a polynucleotide encoding an ERRgamma, thereby reprogramming the cell. In particular embodiments, expression of ERRgamma in the beta-like cell alters the expression level of at least one, two, three, four, five or more polypeptides in the cell, and or increases mitochondrial metabolic activity.

In one embodiment, the polypeptide is administered to beta-like cells in vitro and then the cells containing the polypeptide (or nucleic acid molecules encoding them) are administered to a patient to ameliorate, for example, type 1 diabetes, type 2 diabetes, pre-diabetes, and the treatment of other metabolic diseases or disorders associated with a deficiency in beta cell number (e.g., a reduction in the number of pancreatic cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose-stimulated insulin secretion, a deficiency in insulin production). Administration may be by any means sufficient to increase the number of insulin-secreting beta cells in the subject. In various embodiments, ERRgamma-expressing cells are administered by local injection to a site of disease or injury, by sustained infusion, or by micro-injection under surgical conditions (Wolff et al., Science 247:1465, 1990). In other embodiments, the fusion polypeptides are administered systemically to a tissue or organ of a patient having a deficiency in cell number that can be ameliorated by cell regeneration or reprogramming.

In another approach ERRgamma is introduced into a cultivatable cell type ex vivo (e.g., an autologous or heterologous primary cell or progeny thereof), after which the cell (or its descendants) are injected into a target tissue at the site of disease or injury. In some embodiments, the cells are present in a cellular matrix that provides for their survival, proliferation, or biological activity. Another therapeutic approach included in the invention involves administration of an ERRgamma fusion polypeptide (e.g., ERRgamma fused to a detectable moiety).

In other embodiments, therapeutic polypeptides of the invention are produced in a cell transduced with a viral (e.g., retroviral, adenoviral, and adeno-associated viral) vector that is used for somatic cell gene therapy, especially because of their high efficiency of infection and stable integration and expression (see, e.g., Cayouette et al., Human Gene Therapy 8:423-430, 1997; Kido et al., Current Eye Research 15:833-844, 1996; Bloomer et al., Journal of Virology 71:6641-6649, 1997; Naldini et al., Science 272:263-267, 1996; and Miyoshi et al., Proc. Natl. Acad. Sci. U.S.A. 94:10319, 1997). For example, a nucleic acid molecule, or a portion thereof, that encodes a ERRgamma protein of the invention can be cloned into a retroviral vector and expression can be driven from its endogenous promoter, from the retroviral long terminal repeat, or from a promoter specific for a target cell type of interest (e.g., a cell of the central nervous system). Other viral vectors that can be used include, for example, a vaccinia virus, a bovine papilloma virus, or a herpes virus, such as Epstein-Barr Virus (also see, for example, the vectors of Miller, Human Gene Therapy 15-14, 1990; Friedman, Science 244:1275-1281, 1989; Eglitis et al., BioTechniques 6:608-614, 1988; Tolstoshev et al., Current Opinion in Biotechnology 1:55-61, 1990; Sharp, The Lancet 337:1277-1278, 1991; Cornetta et al., Nucleic Acid Research and Molecular Biology 36:311-322, 1987; Anderson, Science 226:401-409, 1984; Moen, Blood Cells 17:407-416, 1991; Miller et al., Biotechnology 7:980-990, 1989; Le Gal La Salle et al., Science 259:988-990, 1993; and Johnson, Chest 107:77S-83S, 1995). Retroviral vectors are particularly well developed and have been used in clinical settings (Rosenberg et al., N. Engl. J. Med 323:370, 1990; Anderson et al., U.S. Pat. No. 5,399,346). Most preferably, a viral vector is used to administer the gene of interest systemically or to a cell at the site that requires cell reprogramming or an increase in regeneration.

Selected cells of the invention may be employed in therapeutic or prophylactic methods following isolation. Accordingly, the present invention provides methods of treating, for example, type 1 diabetes, type 2 diabetes, pre-diabetes, and the treatment of other metabolic diseases or disorders associated with a deficiency in beta cell number (e.g., a reduction in the number of pancreatic cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose-stimulated insulin secretion, a deficiency in insulin production) or symptoms thereof which comprise administering a therapeutically effective amount of a pharmaceutical composition comprising a cell expressing ERRgamma to a subject (e.g., a mammal such as a human). Thus, one embodiment is a method of treating a subject suffering from or susceptible to type 1 diabetes, type 2 diabetes, pre-diabetes, or a symptom thereof. The method includes the step of administering to the mammal a therapeutic amount of a cell herein sufficient to treat the disease or disorder or symptom thereof, under conditions such that the disease or disorder is treated.

The methods herein include administering to the subject (including a subject identified as in need of such treatment) an effective amount of a cellular composition described herein, or a composition described herein to produce such effect. Identifying a subject in need of such treatment can be in the judgment of a subject or a health care professional and can be subjective (e.g. opinion) or objective (e.g. measurable by a test or diagnostic method).

The therapeutic methods of the invention (which include prophylactic treatment) in general comprise administration of a therapeutically effective amount of a cellular composition described herein, to subjects, particularly humans, suffering from, having susceptibility to, or at risk of having type 1 diabetes, type 2 diabetes, pre-diabetes, or another metabolic disease or disorder associated with a deficiency in beta cell number (e.g., a reduction in the number of pancreatic cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose-stimulated insulin secretion, a deficiency in insulin production). Determination of those subjects “at risk” can be made by any objective or subjective determination by a diagnostic test or opinion of a subject or health care provider (e.g., genetic test, enzyme or protein marker, Marker (as defined herein), family history, and the like).

In one embodiment, the invention provides a method of monitoring treatment progress in connection with type 1 diabetes, type 2 diabetes, pre-diabetes, and the treatment of other metabolic diseases or disorders associated with a deficiency in beta cell number (e.g., a reduction in the number of pancreatic cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose-stimulated insulin secretion, a deficiency in insulin production). The method includes the step of determining a level of diagnostic marker (Marker) (e.g., any target delineated herein in a subject suffering from or susceptible to a disorder or symptoms thereof associated with a defect in beta cell number or activity, in which the subject has been administered a therapeutic amount of a cellular composition described herein sufficient to treat the disease or symptoms thereof. The level of Marker determined in the method can be compared to known levels of Marker in either healthy normal controls or in other afflicted patients to establish the subject's disease status. In preferred embodiments, a second level of Marker in the subject is determined at a time point later than the determination of the first level, and the two levels are compared to monitor the course of disease or the efficacy of the therapy. In certain preferred embodiments, a pre-treatment level of Marker in the subject is determined prior to beginning treatment according to this invention; this pre-treatment level of Marker can then be compared to the level of Marker in the subject after the treatment commences, to determine the efficacy of the treatment.

In some embodiments, it may be desirable to maintain the selected cells in culture for hours, days, or even weeks prior to administering them to a subject. Media and reagents for tissue culture are well known in the art (see, for example, Pollard, J. W. and Walker, J. M. (1997) Basic Cell Culture Protocols, Second Edition, Humana Press, Totowa, N.J.; Freshney, R.I. (2000) Culture of Animal Cells, Fourth Edition, Wiley-Liss, Hoboken, N.J.). Examples of suitable media for incubating/transporting beta-like cells expressing ERRgamma include, but are not limited to, Dulbecco's Modified Eagle Medium (DMEM), RPMI media, Hanks' Balanced Salt Solution (HBSS) phosphate buffered saline (PBS), and L-15 medium. Examples of appropriate media for culturing cells of the invention include, but are not limited to, Dulbecco's Modified Eagle Medium (DMEM), DMEM-F12, RPMI media, EpiLlfe medium, and Medium 171. The media may be supplemented with fetal calf serum (FCS) or fetal bovine serum (FBS) as well as antibiotics, growth factors, amino acids, inhibitors or the like, which is well within the general knowledge of the skilled artisan.

Formulations

Compositions of the invention comprising purified cells can be conveniently provided as sterile liquid preparations, e.g., isotonic aqueous solutions, suspensions, emulsions, dispersions, or viscous compositions, which may be buffered to a selected pH. Liquid preparations are normally easier to prepare than gels, other viscous compositions, and solid compositions. Additionally, liquid compositions are somewhat more convenient to administer, especially by injection. Viscous compositions, on the other hand, can be formulated within the appropriate viscosity range to provide longer contact periods with specific tissues. Liquid or viscous compositions can comprise carriers, which can be a solvent or dispersing medium containing, for example, water, saline, phosphate buffered saline, polyol (for example, glycerol, propylene glycol, liquid polyethylene glycol, and the like) and suitable mixtures thereof.

Sterile injectable solutions can be prepared by incorporating the genetically modified beta-like cells utilized in practicing the present invention in the required amount of the appropriate solvent with various amounts of the other ingredients, as desired. Such compositions may be in admixture with a suitable carrier, diluent, or excipient such as sterile water, physiological saline, glucose, dextrose, or the like. The compositions can also be lyophilized. The compositions can contain auxiliary substances such as wetting, dispersing, or emulsifying agents (e.g., methylcellulose), pH buffering agents, gelling or viscosity enhancing additives, preservatives, flavoring agents, colors, and the like, depending upon the route of administration and the preparation desired. Standard texts, such as “REMINGTON'S PHARMACEUTICAL SCIENCE”, 17th edition, 1985, incorporated herein by reference, may be consulted to prepare suitable preparations, without undue experimentation.

Various additives which enhance the stability and sterility of the compositions, including antimicrobial preservatives, antioxidants, chelating agents, and buffers, can be added. Prevention of the action of microorganisms can be ensured by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, and the like. Prolonged absorption of the injectable pharmaceutical form can be brought about by the use of agents delaying absorption, for example, aluminum monostearate and gelatin. According to the present invention, however, any vehicle, diluent, or additive used would have to be compatible with the genetically modified beta-like cells or their progenitors or descendants.

The compositions can be isotonic, i.e., they can have the same osmotic pressure as blood and lacrimal fluid. The desired isotonicity of the compositions of this invention may be accomplished using sodium chloride, or other pharmaceutically acceptable agents such as dextrose, boric acid, sodium tartrate, propylene glycol or other inorganic or organic solutes. Sodium chloride is preferred particularly for buffers containing sodium ions.

Viscosity of the compositions, if desired, can be maintained at the selected level using a pharmaceutically acceptable thickening agent. Methylcellulose is preferred because it is readily and economically available and is easy to work with. Other suitable thickening agents include, for example, xanthan gum, carboxymethyl cellulose, hydroxypropyl cellulose, carbomer, and the like. The preferred concentration of the thickener will depend upon the agent selected. The important point is to use an amount that will achieve the selected viscosity. Obviously, the choice of suitable carriers and other additives will depend on the exact route of administration and the nature of the particular dosage form, e.g., liquid dosage form (e.g., whether the composition is to be formulated into a solution, a suspension, gel or another liquid form, such as a time release form or liquid-filled form).

Those skilled in the art will recognize that the components of the compositions should be selected to be chemically inert and will not affect the viability or efficacy of the genetically modified cells as described in the present invention. This will present no problem to those skilled in chemical and pharmaceutical principles, or problems can be readily avoided by reference to standard texts or by simple experiments (not involving undue experimentation), from this disclosure and the documents cited herein.

One consideration concerning the therapeutic use of genetically modified beta-like cells of the invention is the quantity of cells necessary to achieve an optimal effect. The quantity of cells to be administered will vary for the subject being treated. In a one embodiment, between 10⁴ to 10⁸, between 10⁵ to 10⁷, or between 10⁶ and 10⁷ genetically modified beta-like cells of the invention are administered to a human subject. In preferred embodiments, at least about 1×10⁷, 2×10⁷, 3×10⁷, 4×10⁷, and 5×10⁷ genetically modified beta-like cells of the invention are administered to a human subject. The precise determination of what would be considered an effective dose may be based on factors individual to each subject, including their size, age, sex, weight, and condition of the particular subject. Dosages can be readily ascertained by those skilled in the art from this disclosure and the knowledge in the art.

The skilled artisan can readily determine the amount of cells and optional additives, vehicles, and/or carrier in compositions to be administered in the methods of the invention. Typically, any additives (in addition to the active stem cell(s) and/or agent(s)) are present in an amount of 0.001 to 50% (weight) solution in phosphate buffered saline, and the active ingredient is present in the order of micrograms to milligrams, such as about 0.0001 to about 5 wt %, preferably about 0.0001 to about 1 wt %, still more preferably about 0.0001 to about 0.05 wt % or about 0.001 to about 20 wt %, preferably about 0.01 to about 10 wt %, and still more preferably about 0.05 to about 5 wt %. Of course, for any composition to be administered to an animal or human, and for any particular method of administration, it is preferred to determine therefore: toxicity, such as by determining the lethal dose (LD) and LD50 in a suitable animal model e.g., rodent such as mouse; and, the dosage of the composition(s), concentration of components therein and timing of administering the composition(s), which elicit a suitable response. Such determinations do not require undue experimentation from the knowledge of the skilled artisan, this disclosure and the documents cited herein. And, the time for sequential administrations can be ascertained without undue experimentation.

Administration of ERRgamma Cells

Compositions comprising an ERRgamma expressing beta-like cell of the invention or their progenitors/descendants can be provided systemically or directly to a subject for the treatment or prevention of type 1 diabetes, type 2 diabetes, pre-diabetes, and the treatment of other metabolic diseases or disorders associated with a deficiency in beta cell number (e.g., a reduction in the number of pancreatic cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose-stimulated insulin secretion, a deficiency in insulin production). In one embodiment, cells of the invention are directly injected into an organ of interest (e.g., pancreas). Alternatively, compositions comprising beta-like cells of the invention are provided indirectly to the organ of interest, for example, by administration into the circulatory system (e.g., the pancreatic vasculature). Expansion and differentiation agents can be provided prior to, during or after administration of the cells to increase production of cells having insulin-producing potential in vitro or in vivo. The cells can be administered in any physiologically acceptable vehicle, normally intravascularly, although they may also be introduced into another convenient site where the cells may find an appropriate site for regeneration and differentiation.

In one approach, at least 100,000, 250,000, or 500,000 cells are injected. In other embodiments, 750,000, or 1,000,000 cells are injected. In other embodiments, at least about 1×10⁵ cells will be administered, 1×10⁶, 1×10⁷, or even as many as 1×10⁸ to 1×10¹⁰, or more are administered. Selected cells of the invention can comprise a purified population of cells that expresses ERRgamma. Preferable ranges of purity in populations comprising selected cells are about 50 to about 55%, about 55 to about 60%, and about 65 to about 70%. More preferably the purity is at least about 70%, 75%, or 80% pure, more preferably at least about 85%, 90%, or 95% pure. In some embodiments, the population is at least about 95% to about 100% selected cells. Dosages can be readily adjusted by those skilled in the art (e.g., a decrease in purity may require an increase in dosage). The cells can be introduced by injection, catheter, or the like.

Compositions of the invention include pharmaceutical compositions comprising genetically modified beta-like cells or their progenitors and a pharmaceutically acceptable carrier. Administration can be autologous or heterologous. For example, beta-like cells, or progenitors can be obtained from one subject, and administered to the same subject or a different, compatible subject.

Selected cells of the invention or their progeny (e.g., in vivo, ex vivo or in vitro derived) can be administered via localized injection, including catheter administration, systemic injection, localized injection, intravenous injection, or parenteral administration. When administering a therapeutic composition of the present invention (e.g., a pharmaceutical composition containing a selected cell), it will generally be formulated in a unit dosage injectable form (solution, suspension, emulsion).

Accordingly, the invention also relates to a method of treating a subject having, for example, type 1 diabetes, type 2 diabetes, pre-diabetes, or another metabolic disease or disorder associated with a deficiency in beta cell number (e.g., a reduction in the number of pancreatic cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose-stimulated insulin secretion, a deficiency in insulin production). This method comprises administering to the subject an effective amount either of a stem/progenitor cell isolated as explained herein or of a cellular extract derived from such a cell.

In another pharmaceutical use, stem/progenitor cells of the present invention can be genetically modified prior to their administration to a subject. For this purpose, the cells can be transformed with a nucleic acid encoding the protein that is to be produced in the cells. The nucleic acid can be introduced into cells of the invention using any of the various methods that are well known to the skilled person, for example, using a viral vector and/or a lipid containing transfection composition such as IBAfect (IBA GmbH, Goettingen, Germany), Fugene (Roche), GenePorter (Gene Therapy Systems), Lipofectamine (Invitrogen), Superfect (Qiagen), Metafecten (Biontex) or those ones described in the PCT application WO 01/015755). In a related embodiment, the cells of the invention, after being transformed with a nucleic acid encoding a polypeptide of choice, can be used to recombinantly produce this polypeptide.

Methods of Treatment

Provided herein are methods for treating or preventing type 1 diabetes, type 2 diabetes, pre-diabetes, and the treatment of other metabolic diseases or disorders associated with a deficiency in beta cell number (e.g., a reduction in the number of beta cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose stimulated insulin secretion, a deficiency in insulin production) in a subject. In particular embodiments, the invention provides methods for treating or preventing type 1 diabetes, type 2 diabetes, pre-diabetes, and the treatment of other metabolic diseases or disorders associated with a deficiency in beta cell number (e.g., a reduction in the number of pancreatic cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose-stimulated insulin secretion, a deficiency in insulin production). Patients having diabetes or a metabolic disorder are generally identified by a reduction in beta cell activity or function, for example, by monitoring serum sugar levels in the blood.

In general, the methods comprise administering selected cells of the invention in an amount effective to achieve the desired effect, be it palliation of an existing condition or prevention of recurrence. For treatment, the amount administered is an amount effective in producing the desired effect. An effective amount can be provided in one or a series of administrations. An effective amount can be provided in a bolus or by continuous perfusion.

An “effective amount” (or, “therapeutically effective amount”) is an amount sufficient to affect a beneficial or desired clinical result upon treatment. An effective amount can be administered to a subject in one or more doses. In terms of treatment, an effective amount is an amount that is sufficient to palliate, ameliorate, stabilize, reverse or slow the progression of the disease, or otherwise reduce the pathological consequences of the disease. The effective amount is generally determined by the physician on a case-by-case basis and is within the skill of one in the art. Several factors are typically taken into account when determining an appropriate dosage to achieve an effective amount. These factors include age, sex and weight of the subject, the condition being treated, the severity of the condition and the form and effective concentration of beta-like cells administered.

Suitable human subjects for therapy typically comprise two treatment groups that can be distinguished by clinical criteria. The subjects can have an advanced form of disease, in which case the treatment objective can include mitigation or reversal of disease progression, and/or amelioration of side effects. The subjects can have a history of the condition, for which they have already been treated, in which case the therapeutic objective will typically include a decrease or delay in the risk of recurrence.

Kits

The invention provides kits for the treatment or prevention of type 1 diabetes, type 2 diabetes, pre-diabetes, and the treatment of other metabolic diseases or disorders associated with a deficiency in beta cell number (e.g., a reduction in the number of pancreatic cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose-stimulated insulin secretion, a deficiency in insulin production). In one embodiment, the kit includes a therapeutic or prophylactic composition containing an effective amount of a cell (e.g., a beta-like cell) that expresses ERRgamma in unit dosage form. In some embodiments, the kit comprises a sterile container which contains a therapeutic or prophylactic cellular composition; such containers can be boxes, ampules, bottles, vials, tubes, bags, pouches, blister-packs, or other suitable container forms known in the art. Such containers can be made of plastic, glass, laminated paper, metal foil, or other materials suitable for holding medicaments.

If desired a cell of the invention is provided together with instructions for administering the cell to a subject having or at risk of developing type 1 diabetes, type 2 diabetes, pre-diabetes, or a metabolic disease or disorder associated with a deficiency in beta cell number (e.g., a reduction in the number of pancreatic cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose-stimulated insulin secretion, a deficiency in insulin production). The instructions will generally include information about the use of the composition for the treatment or prevention of type 1 diabetes, type 2 diabetes, pre-diabetes, or a metabolic disease or disorder associated with a deficiency in beta cell number (e.g., a reduction in the number of pancreatic cells) or an insufficient level of beta cell biological activity (e.g., a deficiency in glucose-stimulated insulin secretion, a deficiency in insulin production). In other embodiments, the instructions include at least one of the following: description of the cells; dosage schedule and administration for treatment or prevention of type 1 diabetes, type 2 diabetes, pre-diabetes or symptoms thereof; precautions; warnings; indications; counter-indications; overdosage information; adverse reactions; animal pharmacology; clinical studies; and/or references. The instructions may be printed directly on the container (when present), or as a label applied to the container, or as a separate sheet, pamphlet, card, or folder supplied in or with the container.

The practice of the present invention employs, unless otherwise indicated, conventional techniques of molecular biology (including recombinant techniques), microbiology, cell biology, biochemistry and immunology, which are well within the purview of the skilled artisan. Such techniques are explained fully in the literature, such as, “Molecular Cloning: A Laboratory Manual”, second edition (Sambrook, 1989); “Oligonucleotide Synthesis” (Gait, 1984); “Animal Cell Culture” (Freshney, 1987); “Methods in Enzymology” “Handbook of Experimental Immunology” (Weir, 1996); “Gene Transfer Vectors for Mammalian Cells” (Miller and Calos, 1987); “Current Protocols in Molecular Biology” (Ausubel, 1987); “PCR: The Polymerase Chain Reaction”, (Mullis, 1994); “Current Protocols in Immunology” (Coligan, 1991). These techniques are applicable to the production of the polynucleotides and polypeptides of the invention, and, as such, may be considered in making and practicing the invention. Particularly useful techniques for particular embodiments will be discussed in the sections that follow.

The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the assay, screening, and therapeutic methods of the invention, and are not intended to limit the scope of what the inventors regard as their invention.

EXAMPLES Example 1 Postnatal Islets Acquired Oxidative Features

Beta cells are known to functionally mature postnatally, including acquiring the ability to robustly secrete insulin in response to glucose. Consistent with an immature phenotype, islets isolated from 2 week-old neonatal mice were unable to secrete insulin in response to a glucose challenge (FIG. 1A). To identify important pathways required for glucose-stimulated insulin secretion (GSIS), the transcriptomes of isolated islets during postnatal maturation were compared. Consistent with beta cell terminal differentiation being essentially completed postnatally, and the fact that adult cells were formed by self-duplication rather than stem cell differentiation ENREF 13 (Dor et al., 2004, Adult pancreatic beta-cells are formed by self-duplication rather than stem-cell differentiation. Nature 429, 41-46), the expression of genes known to regulate pancreatic endocrine development in rodents and humans were largely unchanged postnatally (FIG. 2A, Table 2, Conrad et al., 2014, Trends in endocrinology and metabolism: TEM, 25(8): 407-414).

Increased Pdx1, MafA and Nkx6.1, and decreased MafB expression were observed with maturation (FIG. 2A), in agreement with these genes being required for adult beta cell function (Conrad et al., 2014, Trends in endocrinology and metabolism: TEM, 25(8): 407-414). Functional analyses of the transcriptomes revealed that genes involved in cell proliferation were down-regulated during islet maturation, including known positive beta cell proliferation regulators Pdgfr, Pdgfr, Pdgf and Fgfr1 (FIG. 1B, Table 1, and FIG. 2B and FIG. 2C), in line with the observed decline in clonal beta cell expansion in adult islets (Chen et al., 2011, Nature 478, 349-355; Hart et al., 2000, Nature 408, 864-868; Teta et al., 2005, Diabetes 54, 2557-2567; Dor et al., 2004, Nature 429, 41-46). In contrast, up-regulated genes were associated with metabolic pathways, particularly glucose metabolism and ATP biosynthesis pathways, including electron transport chain (ETC), Oxidative Phosphorylation (OxPhos) and ion channel-related exocytosis. Without being bound to a particular theory, induction of metabolic genes may be important for GSIS, given the high mitochondrial activity of adult beta cells. Consistent with this hypothesis, mitochondria genes known to regulate GSIS, including malate dehydrogenase (Mdh1), pyruvate carboxylase (Pcx), and components of OxPhos including Cox6a2, Ndufa4 and Ndufs2 (Xu et al., 2008, Diabetologia 51, 2022-2030; Zhao et al., 1998, FEBS letters 430, 213-216), were more highly expressed, while lactate dehydrogenase (Ldha), a suppressor of GSIS, had reduced expression in adult compared to neonatal beta cells (FIG. 1C and FIG. 1F, Table 1). Without being bound to a particular theory, these results indicate that an important metabolic transition occurs in islet beta cells during postnatal functional maturation. Of particular note, expression of ERRgamma, a known mitochondrial gene regulator, was progressively induced during islet maturation (FIG. 1C and FIG. 1D). This induction of ERRgamma expression was similarly observed in beta cells isolated from mouse insulin-GFP (MIP-GFP) mice, where ERRgamma expression was ˜5 fold higher in adult compared to neonatal beta cells (FIG. 3A and FIG. 3B). These findings, combined with the predominant expression of ERRgamma in endocrine islets compared to exocrine cells and the positive staining of islets in ERRgamma-LacZ knock-in mice (Alaynick et al., 2007, Cell metabolism 6, 13-24), indicate a specific role for ERRgamma in orchestrating a metabolic transition in endocrine cells required for GSIS (FIG. 1E).

Example 2 ERRgamma was Required for Glucose-Stimulated Insulin Secretion

To investigate the role of ERRgamma in the functional maturation of pancreatic beta cells, beta cell-specific ERRgamma knockout (betaERRgammaKO) mice were generated by crossing ERRgamma^(lox/lox) mice with rat insulin 2 promoter (RIP)-Cre mice. ERRgammaKO mice were born at the expected Mendelian frequency and exhibited normal body weights and life expectancies (FIG. 4A and FIG. 4B). The RIP-Cre recombinase selectively decreased ERRgamma expression by 80% in ERRgammaKO compared to wild-type ERRgamma^(lox/lox) islets without significantly affecting hypothalamic ERRgamma expression (FIG. 4A and FIG. 4B), in agreement with recent similar reports (Tang et al., 2003, Cell metabolism 18, 883-895). Monitoring ad lib fed blood glucose levels of ERRgammaKO mice revealed a transient increase in female mice that was resolved by 8 weeks of age (FIG. 4C and FIG. 4D). However, at 8 weeks of age, both male and female ERR KO mice were glucose-intolerant compared to ERR^(lox/lox) (WT) and RIP-Cre (WT(RIP-Cre)) cohorts, as determined by glucose tolerance tests (GTTs) (FIG. 5A and FIG. 6A). While no significant differences in insulin sensitivity were seen, ERR KO mice failed to increase insulin secretion in response to a glucose challenge (FIGS. 5C and 5D, and FIGS. 6C and 6D). Notably, this ERR KO phenotype was exaggerated by metabolic stress; ERR KO mice fed a high fat-high sucrose diet for 4 weeks from 4 weeks of age displayed more pronounced glucose intolerance and defects in insulin secretion, without any significant change in insulin sensitivity (FIG. 5B, FIG. 5E, and FIG. 6B, FIG. 6E).

The inability of ERR KO mice to secrete insulin in response to a glucose challenge was phenocopied in both inducible beta cell-specific deletion (ERR KO ER+Tam) and pancreatic-specific ERR KO (PERR KO) mouse models. ERR KO ER mice treated with tamoxifen (7 days sequential i.p. injection) showed a 75% reduction in islet ERRgamma expression and exhibited glucose intolerance similar to that observed in the developmental ERR KO mice (FIGS. 6F and 6G). Furthermore, mice lacking ERRgamma in the entire pancreas, generated by crossing ERR^(lox/lox) mice with PDX1-Cre mice (PERR KO mice), displayed impaired glucose tolerance compared to WT mice (FIGS. 7A-7D). Without being bound to a particular theory, collectively these results indicate that islet ERRgamma expression is essential for proper GSIS function and whole-body glucose homeostasis when challenged with elevated blood glucose levels.

Morphologically, islets isolated from ERR KO mice maintained on a normal chow diet were indistinguishable from control islets, based on hematoxylin and eosin (H&E) staining and immunohistochemical analysis (FIG. 8A). However, when stressed by a high fat diet (HFD), ERR KO islets were larger with significant increases in beta cell mass, as measured by insulin content and islet size, compared to control islets (FIGS. 5F and 5G, and FIGS. 8A-8F).

Without being bound to a particular theory, the above observations are indicative of a defect in GSIS in ERR KO mice. To test this hypothesis, the effect of transient ERR gamma deletion ex vivo on GSIS was investigated. Adenoviral-induced Cre-recombination in ERR^(lox/lox) (Ad-ERR KO) islets reduced ERR gamma expression by ˜75% compared to control adenovirus EGFP-ERR^(lox/lox) (Ad-Control) islets without affecting insulin2 (Ins2) expression (FIG. 5H). Notably, the ability of Ad-ERR KO islets to secrete insulin in response to a glucose challenge was almost totally abrogated ex vivo (FIG. 5I). Furthermore, loss of ERR in the entire pancreas (PERR KO mice) reduced islet insulin secretion in response to nutrients (FIG. 5K). As ERRgamma regulates mitochondrial oxidative phosphorylation and metabolism in heart (Alaynick et al., 2007, Cell metabolism 6, 13-24; Dufour et al., 2007, Cell metabolism 5, 345-356) and skeletal muscle (Zhao et al., 1998, FEBS letters 430, 213-216), it was investigated whether ERRgamma is required for mitochondrial function in islets. Ad-Control islets responded robustly with a 2-fold increase in their oxygen consumption rate (OCR) when stimulated with 20 mM glucose. In contrast, Ad-ERR KO islets failed to increase their OCR in response to the glucose challenge (FIG. 5J). Consistent with these results, ERR gamma knockdown in the rat clonal beta cell line INS-1 similarly reduced OCR, cellular ATP production and GSIS function in response to a glucose challenge (FIGS. 9A-9D). Without being bound to a particular theory, these results indicate that ERRgamma regulation of beta cell energy metabolism is required for GSIS.

Example 3 ERRgamma was Required for Beta Cell Metabolic Maturation

As mitochondrial function and morphology are tightly correlated (Tang et al., 2013, Cell metabolism 18, 883-895; Narkar et al., Cell metabolism 13, 283-293), it was investigated whether structural changes were detectable in ERR KO beta cell mitochondria. Electron microscopy revealed that the insulin and proinsulin granules, and the overall mitochondrial number were not affected by ERRgamma deletion (FIGS. 10A and 10B). However, mitochondria swelling with disrupted cristae structure was seen in the ERRgamma-deficient beta cells, with significant increases in mitochondrial length, width, and volume, hallmarks of functionally defective mitochondria (FIGS. 10A-10C).

To understand the molecular role of ERRgamma in beta cell function, the transcriptional consequences of ERRgamma deletion were determined. In the developmentally-deleted ERRgammaKO islets, RNA-Seq revealed that the expression of 4189 genes was altered, with almost equal numbers of genes down- and up-regulated (2008 and 2181 genes, respectively; false discovery rate [FDR]<0.01, fold change [FC]>1.5). A similar comparison in the transiently-deleted Ad-ERRgammaKO islets by microarray analysis identified 2205 genes with altered expression, again with similar numbers of genes down- and up-regulated (1207 and 998 genes, respectively; false discovery rate [FDR]<0.01, fold change [FC]>1.25). As defects in GSIS were observed in both ERR KO and Ad-ERR KO islets, Gene Ontology (GO) analysis was performed on the common, differentially-expressed genes (232 down- and 239 up-regulated genes) to identify global cellular processes affected by ERRgamma deletion (FIG. 11 and Table 3). Consistent with the diabetic phenotype, ERRgamma-regulated genes were associated with processes important for beta cell function including ATP biosynthesis, cation transport, oxidative phosphorylation, electron transport and secretion (FIG. 10D). Furthermore, motif analyses of promoter regions identified ERR response elements (ERREs) in more than half of these differentially expressed genes (62.1% of down- and 64.6% of up-regulated genes). Without being bound to a particular theory, this indicates direct regulation by ERRgamma (FIG. 12A). In support of this notion, conventional ChIP assays, performed in the mouse insulinoma cell line MIN-6, confirmed the direct binding of ERRgamma to the promoter regions of Atp2a2 and Mdh1 (FIG. 12B). The expression changes of selected genes relevant to metabolic pathways (Mdh1, Cox6a2, Atp2a2, Ndufs2 and Atp6v0a2) were confirmed by qPCR analysis in both ERR KO and PERR KO islets (Table 4 and FIG. 10E, left and right panels, respectively). Without being bound to a particular theory, these results indicate that ERRgamma is a global regulator of ATP biosynthesis and metabolic genes in islet beta cells.

To further clarify the role of ERRgamma in the functional maturation of beta cells, the postnatal transcriptional changes in islets were compared with those induced by ERRgamma deletion. Notably, loss of ERRgamma abrogated a large number of the developmental changes associated with postnatal beta cell maturation (FIG. 10H). Specifically, the changes in expression of 74 genes normally up-regulated, and 35 genes normally down-regulated during maturation were lost in ERRgammaKO islets (FIG. 10F). These dysregulated genes included genes involved in energy production (ATP biosynthesis, oxidative phosphorylation and ETC) and secretory/exocytosis pathways (FIG. 10G). Without being bound to a particular theory, collectively these results indicate that ERRgamma is not only important for maintaining mitochondrial function in functionally mature beta cells, but also directly orchestrates many of the transcriptional changes that drive the postnatal maturation of these cells.

Example 4 ERRgamma Drives the Maturation of Synthetic Beta Cells

Generation of transplantable beta cells from pluripotent stem cells is a major goal of stem cell therapeutics. However, current iPSC-derived beta-like cells resemble fetal cells in their inability to secrete insulin in response to a glucose challenge (Hackenbrock et al., 1966, The Journal of Cell Biology 30, 269-297; Anello et al., 2005, Diabetologia 48, 282-289; Hrvatin et al., 2014, Proc. Natl. Acad. Sci. 111(8): 3038-3043; D'Amour et al., 2006, Nature Biotechnology 24, 1392-1401; Kroon et al., 2008, Nature Biotechnology 26, 443-452; Schulz et al., 2012, PloS one 7, e37004; Xie et al., 2012, Cell Stem Cell 12, 224-237; Sneddon et al., 2012, Nature 491, 765-768). Based on a proposed regulatory role for ERRgamma in enhancing oxidative metabolism during beta cell maturation, it was investigated whether overexpression of ERRgamma could drive the maturation of human iPSC-derived beta-like cells into mature beta cells, in terms of metabolism. To address this question, the differentiation protocol was optimized for producing insulin-positive beta-like cells from human iPSCs, utilizing a human insulin promoter driven-GFP reporter for screening and isolation (Pagliuca et al., 2014, Development 140, 2472-2483; Hrvatin et al., Proceedings of the National Academy of Sciences of the United States of America; 111(8): 3038-3043.). In the optimized protocol, insulin-positive cells were generated from iPSC, derived from a human endothelial cell line HUVEC, 18-21 days after initiation of differentiation (FIGS. 13A-13C and FIG. 14). Expression profiling during iPSC differentiation confirmed the generation of beta-like cells. Specifically, expression of the pluripotent marker Nanog was lost upon initiation of differentiation, while the terminal beta cell differentiation marker, insulin, appeared 18-21 days after initiation of differentiation. The definitive endoderm marker SOX/7, the pancreatic progenitor marker HNF1 and endocrine progenitor marker SOX9 were transiently increased around days 7, 15 and 18, respectively (FIG. 14). Furthermore, the expression of additional beta cell markers including PDX1, MAFA, PAX6, NEUROD1, GCK, CHGA and VAMP2 were strongly induced at day 21 (FIG. 14). Immunohistochemical analyses confirmed that the optimized, 21 day differentiation protocol yielded beta-like cells that express the beta cell marker PDX1, c-peptide and prohormone carboxylase1/3 (PC1/3) (FIG. 15A). This optimized differentiation protocol reproducibly generated insulin-positive, glucagon-negative-like cells, defined here as iβL cells, and electron microscopy revealed the presence of insulin granules (FIG. 13H and FIGS. 15B-15E). Moreover, while these iPSC-derived beta-like cells failed to secrete c-peptide in response to a glucose challenge, they were responsive to direct cellular depolarization-mediated insulin secretion by KCl (FIG. 15F). This confirmed the expression of Nkx6-1 and MafA in insulin-positive i L cells (FIG. 15H). These results confirmed the generation of human beta-like cells. Without being bound to a particular theory, this indicated that mitochondrial function might be one reason for the defective GSIS function in-like cells.

Given the role of ERRgamma in endogenous beta cell maturation, it was investigated whether overexpression of ERRgamma could rescue GSIS function in iPSC-derived beta-like cells. To address this question, iPSC-derived beta-like cells (day 22-25) were infected with adenoviral ERRgamma (Ad-ERR) or control (Ad-GFP) vector. Gene expression and functional analyses were performed at days 25-30. Given the widespread use of insulin in culture media, c-peptide levels were used as a surrogate measure of beta-like cell-derived insulin. It was found that Ad-ERRgamma infection successfully restored ERRgamma expression in iPSC-derived beta-like cells, but did not significantly affect their intracellular c-peptide content (FIG. 13D left panel, and FIG. 15G). Encouragingly, Ad-ERRgamma infection significantly increased the c-peptide concentration in the culture media (FIG. 13D, right panel). Next the GSIS ability of Ad-ERR infected iPSC-derived beta-like cells was examined. Control infected iPSC-derived beta-like cells (defined as i L^(GFP) cells) were not able to secrete c-peptide in response to a glucose challenge. Remarkably, Ad-ERR infected iPSC-derived beta-like cells (i eta cells) demonstrated enhanced c-peptide secretion in response to a glucose challenge, similar to that recorded for isolated human islets (FIG. 13E). Furthermore, transcriptomic analyses identified increases in i eta cells of genes associated with the generation of precursor metabolites, oxidation reduction, electron transport chain (ETC), oxidative phosphorylation and mitochondrial organization, and decreases in genes associated with cell cycle, without significant increases in the expression of beta cell lineage-specific genes (FIGS. 13F, FIG. 13G, FIG. 13J, FIG. 13K, FIG. 16, and Table 4). Notably, ERRgamma overexpression improved the cristae structure, as well as the respiration function of mitochondria in i eta cells (FIGS. 13H and 13I). Thus, these results describe the generation of a synthetic glucose-responsive beta cell from iPSC. Without being bound to a particular theory, these results support the hypothesis that ERRgamma-regulated mitochondrial metabolic pathways are required for GSIS (FIG. 18E).

The ability to produce transplantable β cells capable of restoring glucose homeostasis in the setting of diabetes is the ultimate therapeutic goal. To determine whether i eta cells function in vivo, a Streptozocin (STZ)-induced diabetic NOD-SCID mouse model was utilized. Blood glucose levels of NOD-SCID mice treated with STZ (180 mg/kg i.p. injection) were monitored daily to confirm hyperglycemia. Twelve (12) days after STZ injection, 10 million iPSC-derived beta-like cells infected with Ad-GFP (i L^(GFP) cells) or Ad-ERR (i eta cells) were transplanted into the kidney capsule (FIG. 17). Human islets and mouse islets were similarly transplanted as positive controls. Remarkably, the blood glucose levels of mice that received the i eta cells began to normalize within days of transplantation, similar to those receiving functional human or mouse islets (FIG. 18A and FIG. 19A). Furthermore, transplanted i eta cells controlled blood glucose levels in recipient mice chronically (56 days, FIG. 18B, FIG. 19B and FIG. 20) and insulin-positive cells were detected in the kidney after chronic treatment (FIG. 21). Importantly, in approximately half of chronically treated i eta cell recipient mice, the blood glucose levels were restored to non-diabetic levels (<250 mg/dL) concomitant with a glucose-responsive phenotype, as demonstrated by glucose tolerance tests, similar to mice that received human islet transplantation (FIG. 18C). Additionally, pronounced improvements in the circadian regulation of metabolism were observed in chronically treated i eta cell recipient mice with normalized blood glucose levels (increased night time respiratory exchange ratio (RER) consistent with improved glucose utilization), and were accompanied by increased night time activity (FIG. 18D). These results demonstrate that genetically engineered ERRgamma expression might be exploited to potentiate GSIS function in beta-like-cells.

The present study shows that the estrogen-related receptor gamma (ERR) expression distinguishes neonatal and adult beta cells, and that ERRgamma is required for the glucose-responsive beta cells. ERRgamma is a known activator of oxidative metabolism and mitochondrial biogenesis. Without being bound to a particular theory, high energy requirements may be needed to achieve and maintain glucose responsiveness. Although it has not been previously possible to differentiate iPSCs to functional beta cells, the results described herein indicate that activation of the ERRgamma gene network has the potential to overcome this metabolic roadblock. Indeed, genome-directed metabolic maturation was an important step in transforming iPSCs-derived fetal-like cells into glucose-responsive cells in vitro. Perhaps more importantly, optimized scale up and purification shows that these converted cells can, via transplantation, effectively rescue type 1 diabetic mice. Importantly, these experiments provide proof-of-concept in vivo that stem cell transplantation is useful as a therapeutic in the treatment of type 1 and type 2 diabetes.

Here, the fundamental discovery that ERRgamma, a known regulator of oxidative mitochondrial metabolism, is required for the functional maturation of beta cells to produce glucose-responsive, transplantable iPSC-derived beta cells (i eta cells) was exploited. Remarkably, transplantation of i eta cells not only restored glucose homeostasis in a severe STZ-induced Type 1 diabetic mouse model, but re-established circadian metabolic rhythmicity to substrate usage.

This is important because poor glucose management is associated with long-term diabetic consequences including diabetic retinopathy, nephropathy and neuropathy. While long-acting insulin formulations and programmable delivery pumps provide therapeutic utility, they fail to fully replicate the glucose-responsiveness of pancreatic cells. Human islet transplantations offer superior glucose management, but require immuno-suppressive drug regimens and are limited by the availability and in vivo viability of the transplanted cells. Though insulin independence can be achieved via islet transplantation, more than 50% of allotransplanted patients and virtually all autotransplanted patients are back on insulin therapy after 5 years. In both situations, transplantation of a larger mass of islets may alleviate some of the limitations. Thus, patient-specific iPSC-derived cells could resolve many of these concerns and is considered one of the central goals of stem cell replacement therapy.

How might ERR work? As fetal development occurs under conditions of low oxygen tension and steady maternal glucose, most physiologic systems including the pancreas are in a poised but not fully functional state at birth. In the postnatal and adult setting, oxidative metabolism becomes dominant and intermittent feeding exposes the pancreas to dramatic changes in glucose levels. Recently, it has been reported that weaning triggers a maturation step in cells which is characterized by enhanced glucose-stimulated oxidative phosphorylation and insulin secretion (Pagliuca et al. 2014, Cell 159, 428-439). The transcriptomic analyses presented in this study indicates that the increased ERRgamma expression in beta cells served as the key driver of the oxidative metabolic gene network. Furthermore, low ERRgamma expression in iPSC-derived beta-like cells might be limiting their ability to secrete insulin. This is consistent with observations that i eta cells, ERRgamma expressing iPSC-derived beta-like cells, activated an oxidative metabolic program and demonstrated glucose-responsive insulin production. However, the key feature of beta cells is their ability to repeatedly secrete insulin in response to a glucose challenge in vivo and in vitro. Importantly, transplantation of i eta cells not only restored glucose homeostasis in a severe STZ-induced Type I diabetic mouse model, but re-established circadian metabolic rhythmicity to substrate usage.

Despite recent advances, including generating functional beta cells from ES cells and the in vivo maturation of in vitro-differentiated pancreatic progenitor cells, the underlying mechanisms of beta cell maturation remain poorly understood. Whereas dynamic chromatin remodeling and sympathetic innervation stimuli are implicated, the finding that ERRgamma coordinates a transcriptional program regulating increased oxidative metabolism provides mechanistic insight into the functional maturation of beta cells (FIG. 18E). Genetic and epidemiology studies have implicated ERRgamma in the development of diabetes (http://t1dbase.org/page/AtlasHome), however its role was previously not understood. Notably, an understanding of the role of ERRgamma in driving the metabolic maturation necessary for the generation of glucose-responsive beta cells has the potential to accelerate the development of insulin-responsive beta cells from the patient's own cells. The results described here indicate that i eta cells represent a new opportunity for stem cell-based therapy.

The experiments described above were performed with the following methods.

Animal Experiments

Beta cell-specific ERRgamma-knockout mice (ERR KO) were generated by crossing ERR^(lox/lox) and RIP-Cre (B6N.Cg-Tg(Ins2-cre)25Mgn/J) mice on a pure C57BL/6J genetic background. Tamoxifen-inducible beta cell-specific ERRgamma-knockout mice were generated by crossing ERR^(lox/lox) and RIP-CreER (STOCK Tg (Ins2-cre/Esr1)1Dam/J) mice. Pancreas-specific ERRgamma-knockout mice (PERR KO) were generated by crossing ERR^(lox/lox) and PDX1-Cre (B6.FVB-Tg(PDX1-cre)6Tuv/J). Insulin promoter GFP (MIP-GFP) mice (Tg(Ins1-EGFP)1Hara) were purchased from Jackson Laboratory. The ERR-LacZ knock-in mice were described previously (Alaynick et al., 2007, Cell metabolism 6, 13-24). Glucose tolerance tests were performed before (12 week-old) and 3 weeks after treatment (16 week-old) of tamoxifen-inducible cell-specific ERR-knockout mice. Male mice were given daily injections of tamoxifen (2 mg/kg in corn oil, intra-peritoneally) for 7 days.

Animals were maintained in a specific pathogen-free animal facility (SPF) on a 12-hour light-dark cycle at an ambient temperature of 23° C. Water and food were provided ad lib. All animal experiments used age- and sex-matched mice. All procedures involving animals were performed in accordance with protocols approved by the IACUC and Animal Resources Department (ARD) of the Salk Institute for Biological Studies.

Intra-Peritoneal Glucose (IP-GTT) or Insulin (IP-ITT) Tolerance Tests

IP-GTTs were performed on overnight fasted mice. Blood glucose values were assessed before and at 15, 30, 60 and 120 minutes after intra-peritoneal administration of 2 g/kg of glucose using glucose PILOT. Serum insulin levels were assessed before and at 5, 15 and 30 min after the intra-peritoneal administration of glucose using a Rat/mouse Insulin ELISA kit (Millipore). IP-ITT assays were performed on mice after a 6 hour fast with the injection of 0.75 U/kg of insulin (Humalin R, Eli Lilly).

Isolated Pancreatic Islet Studies

Mouse pancreatic islets were isolated as previously described for rats (Sutton et al., 1986, Transplantation 42, 689-691). Briefly, 0.5 mg/ml collagenase P (Roche) diluted in HBSS buffer was injected through the common bile duct, and the perfused pancreas dissected and incubated in water bath (37° C. for 21 minutes). Digested exocrine cells and intact islets were separated using Histopaque-1077 (SIGMA) with centrifugation (900 g for 15 minutes) and intact islets were handpicked. All human islets were provided by the Integrated Islets Distribution Program (IIDP) under an approved protocol. Additional information on human islets is provided at Table 5.

Insulin Secretion Assay (Primary Mouse and Human Pancreatic Islets and Human iPSC-Derived Cells)

Insulin release from intact islets was monitored using batch incubation methods. Overnight-cultured isolated pancreatic islets (RPMI-1640 supplemented with 10% (v/v) fetal bovine serum and 1% (v/v) Antibiotic-Antimycotic (Gibco) were pre-cultured at 37° C. for 30 minutes (Krebs Ringer bicarbonate buffer (KRBB) containing 129.4 mM NaCl, 3.7 mM KCl, 2.7 mM CaCl₂, 1.3 mM KH₂PO₄, 1.3 mM MgSO₄, 24.8 mM NaHCO₃ (equilibrated with 5% CO₂, 95% O₂, pH7.4), 10 mM HEPES and 0.2% (v/v) BSA (fraction V, Sigma) (KRBH) with 3 mM glucose). Pancreatic islets were then incubated in KRBH buffer (500 μl/10 islets) with 3 mM or 20 mM glucose to determine insulin secretion levels. After 30 minutes, islets were pelleted by centrifugation and insulin levels determined by ELISA (Rat/mouse Insulin ELISA KIT (Millipore) and Human Insulin ELISA KIT (Millipore) for mouse and human islets, respectively). For human iPSC-derived cells, the cells (1×10⁶ cells/well in 24 well) were pre-cultured in 3 mM glucose KRBH buffer (500 μl/well). The cells were then incubated in KRBH buffer (200 μl/well) with 3 mM or 20 mM glucose to determine c-peptide secretion levels as indicator of insulin secretion levels. After 30 min, the cells were pelleted by centrifugation and c-peptide levels were determined by human c-peptide ELISA KIT (Millipore).

INS-1 Cell Culture, Transfection and Insulin Secretion Assay

INS-1 cells were cultured at 37° C. in 5% CO₂ in air in RPMI-1640 (Sigma Aldrich) supplemented with 10% (v/v) fetal bovine serum, 1% (v/v) Antibiotic-Antimycotic (Gibco) 10 mM HEPES, 2 mM glutamax, 1 mM sodium pyruvate, and 50 M-mercaptoethanol (RPMI for INS-1 medium). INS-1 cells were transfected with Lipofectamine2000 containing Plus Reagent (Invitrogen). INS-1 cells were transfected with ERRgamma siRNA (Qiagen) or negative control scramble siRNA (Qiagen) for 72 hours. Insulin secretion was measured in pre-incubated cells (37° C. for 30 minutes in KRBH with 3 mM glucose, as described in insulin secretion assays for primary islets) after a 30 minute glucose challenge (KRBH buffer with 3 mM or 20 mM glucose) using a Rat/mouse Insulin ELISA kit (Millipore).

Quantitative RT-PCR Analysis

Total RNA was extracted using TRIzol reagent (Invitrogen) and RNeasy KIT (Qiagen). Reverse transcription was performed with a SuperScript III First-Strand Synthesis System kit (Invitrogen) or PrimeScript RT reagent kit (TAKARA). Real time quantitative RT-PCR (qPCR) was performed using SYBR Green (Bio-Rad). PCR analyses were carried out using the oligonucleotide primers listed in Table 6.

Chromatin Immunoprecipitation

Chromatin was prepared from mouse insulinoma, MIN-6 cells. Briefly, MIN-6 cells were cross-linked with 1% formaldehyde for 10 minutes, followed by the addition of glycine at 125 mM. Chromatin was sheared by enzymes (CHIP IT Express Kit, Active Motif) and immuno-precipitated with 2 g anti-H3, control mouse IgG, or anti-ERRgamma antibodies. ChIP-qPCR primers are listed in Table 6.

Electron Microscopy

Pancreatic samples were cut into 1 mm² sections and fixed for 36 hours at 4° C. in 0.1 mM sodium phosphate buffer (pH 7.4) containing 2% paraformaldehyde and 2% glutaraldehyde. The tissue pieces were subsequently washed and dehydrated using graded acetone, and embedded in Epon-Araldite. An ultra microtome was used to prepare ultra-thin sections. The sectioned tissues were stained with 1% toluidine blue borax solution, mounted on copper grids, and double-stained with uranyl acetate prior to examination in a JEM 100 CX-electron microscope.

Histology (H&E Staining, Immunostaining and LacZ Staining)

H&E staining was performed by Pacific Pathology (San Diego). Immunostaining was visualized by ZEISS confocal microscopy analysis using the following antibodies on frozen sections of pancreas and 4% PFA-fixed cells: Insulin ( 1/100, Abcam ab7842), c-peptide ( 1/100, Abcam ab14182), glucagon ( 1/100, Abcam ab10988), somatostatin ( 1/100, Abcam ab103790), Prohormone Carboxylase 1/3 ( 1/100, Millipore AB 10553), Pdx-1 ( 1/100, Abcam ab47267). DAPI-containing mounting media (VECTASHIELD mounting medium for fluorescence) was used for nuclear staining. Whole pancreases from ERRγ knock-in mice (Alaynick et al., 2007, Cell metabolism 6, 13-24) were fixed with paraformaldehyde and glutaraldehyde, and frozen sections stained by X-gal.

Microarray Analyses

Total RNA was extracted from Ad-GFP or Ad-Cre infected islets using Trizol reagent (Invitrogen) and its quality determined by an Agilent 2100 Bioanalyzer. 500 ng of RNA was reverse transcribed into cRNA and biotin-UTP labeled using the Illumina TotalPrep RNA Amplification Kit (Ambion). cRNA was quantified using an Agilent Bioanalyzer 2100 and hybridized to the Illumina mouseRefseq-8v2 Expression BeadChip using standard protocols (Illumina). Image data were converted into unnormalized Sample Probe Profiles using Illumina GenomeStudio. Data were analyzed by GeneSpring GX software. Briefly, per-chip normalizations were set to the 75^(th) percentile, and per-gene normalizations to the median and specific samples. Genes assigned as absent were eliminated from the dataset and genes with an expression difference of 2-fold more than WT were selected. Combination analyses by GO, pathway analyses and cluster analyses were performed using mainly DAVID software (Huang et al., 2009, Nature protocols 4, 44-57; Huang et al., 2009, Nucleic acids research 37, 1-13). The microarray data are deposited in the NCBI Gene Expression Omnibus and accessible through GEO Series accession number GSE56080.

RNA-Seq Library Generation

Total RNA was isolated from cell pellets treated with RNAlater using the RNA mini kit (Qiagen) and treated with DNaseI (Qiagen) for 30 min at room temperature. Sequencing libraries were prepared from 100-500 ng total RNA using the TruSeq RNA Sample Preparation Kit v2 (Illumina) according to the manufacturer's protocol. Briefly, mRNA was purified, fragmented, and used for first- and second-strand cDNA synthesis followed by adenylation of 3′ ends. Samples were ligated to unique adapters and PCR amplified. Libraries were then validated using the 2100 BioAnalyzer (Agilent), normalized and pooled for sequencing.

High-Throughput Sequencing and Analysis

RNA-Seq libraries prepared from 2-3 biological replicates for each experimental condition were sequenced on the Illumina HiSeq 2500 using bar-coded multiplexing and a 100 bp read length. Image analysis and base calling were performed with Illumina CASAVA-1.8.2. This yielded a median of 29.9M usable reads per sample. Short read sequences were mapped to a UCSC mm9 reference sequence using the RNA-Seq aligner STAR (Dobin et al., 2013, Bioinformatics 29, 15-21). Known splice junctions from mm9 were supplied to the aligner and de novo junction discovery was also permitted. Differential gene expression analysis, statistical testing and annotation were performed using Cuffdiff 2 (Trapnell et al., 2013, Nature biotechnology 31, 46-53). Transcript expression was calculated as gene-level relative abundance in fragments per kilobase of exon model per million (fpkm) mapped fragments and employed correction for transcript abundance bias (Roberts et al., 2011, Bioinformatics 27, 2325-2329). RNA-Seq results for genes of interest were also explored visually using the UCSC Genome Browser. RNA-Seq data can be accessed on the NCBI Sequence Read Archive under the accessions SRP048600 and SRP048605.

Differentiation of Human Induced Pluripotent Cells (hiPSC) to Insulin-Producing Cells and Glucose-Responsive Cells

Human induced pluripotent stem cells derived from Huvec (hiPSC) and embryonic stem cells (H9ES) were obtained from the Stem Cell Core (Salk Institute). Cells were maintained on matrigel (BD)-coated dishes in complete mTeSR Media. For pancreatic differentiation, hPCs were infected with a human insulin reporter lentivirus (pGreenZero lenti reporter human insulin, System Biosciences) by Spinfection (800 g, 1 hour) and then media was changed to 100 ng/ml human Activin (Sigma), 25 ng/ml recombinant human Wnt3a (Sigma) in differentiation media (800 ml DMEM/F12, 13.28 g BSA, 10 ml Glutamax, 560 mg NaHCO₃, 330 mg thiamine, 100 mg reduced glutathione, 3300 mg Vitamin C, 14 μg Selenium, 10 ml NEAA, 2 ml Trace Element B, 1 ml Trace Element C, 7 μl β-ME, 2 ml DLC, 2 ml GABA, 2 ml LiC1, 129.7 ug PA, Insulin 2 mg up to 1000 ml) for 2 days and then 100 ng/ml human Activin in differentiation media for another 2 days (Stage 1). Subsequently, media was replaced with differentiation media with dorsomorphin (Calbiochem), 2 μM Retinoic Acid (Sigma), and 10 μM SB431542 for 7 days (Stage 2). Media was then replaced with differentiation media with 10 μM Forskolin (Sigma), 10 μM dexamethasone (Stemgent), 10 μM TGF RI Kinase inhibitor II (Calbiochem), 10 mM Nicotinamide (Sigma) for 10 days (stage 3). Media was replaced every day (stage 1), every day or every other day (stage 2) and every other day (stage 3, beta-like-cells).

At days 22-25, the expression of human insulin genes and GFP were confirmed regularly by qPCR and fluorescence microscopy. Positive cells were used in subsequent experiments. EGFP-adenovirus (Ad-GFP) or human ERRgamma adenovirus (Ad-ERR) were diluted in RPMI-1640 with 2% FCS, and 1×10⁸ pfu/ml (MOI 100) used to infect beta-like cells for 2 hours. Media was changed to differentiation media containing 10 μM Forskolin (Sigma), 10 μM dexamethasone (Stemgent), 10 μM TGF RI Kinase inhibitor II (Calbiochem), 10 mM Nicotinamide (Sigma) for 3-5 days, then GFP-expressing beta-like cells (iGFP cells) and ERRgamma expressing beta-like-cells (i eta cells) were analyzed for RNA-Seq, EM, Seahorse and transplantation studies. Additional information for differentiation protocol is listed in Table 7.

OCR and ECAR Measurements

Oxygen consumption rates (OCRs) and extracellular acidification rates (ECARs) were recorded in 96-well plates using an XF96 seahorse (Seahorse Biosciences). Briefly, 70 isolated islets/well were pre-cultured with XF DMEM media (pH7.4) and 3 mM glucose for 1 hour prior to the incremental addition of glucose, up to a final concentration of 20 mM. OCRs (reported as % change compared to 3 mM glucose) were recorded during the addition of glucose. Insulin-positive beta-like cells, sorted by flow cytometry, were cultured for 3 days in 96-well plates (1×10⁵ cells/well) prior to infection with adenoviral EGFP or ERRgamma vectors. Infected cells were pre-cultured in XF DMEM media (pH 7.4) with 3 mM glucose for 1 hour, then the media was changed to XF DMEM media (pH 7.4) with 20 mM glucose, 1 mM sodium pyruvate, and appropriate mitochondrial stress reagents (oligomycin, Fccp, Rotenone and Antimycin A), as instructed in the Mitostress Kit (Seahorse Biosciences).

Virus Production

Lentiviruses were produced using 2^(nd) generation or 3^(rd) generation lentiviral systems in HEK293T cell line. Adenovirus EGFP and Cre were purchased from Illinois University and Adenovirus ERRgamma was purchased from Welgen, Inc.

NOD-SCID Mice Transplantation Study

Immunodeficient NOD-SCID mice (NOD.Cg-Prkdcscid I12rgtm1Wj1/SzJ) were purchased from Jackson Laboratory and bred and maintained in autoclaved cages in a SPF facility at the Salk Institute. Mice were rendered diabetic by a single intra-peritoneal (i.p.) high dose of streptozotocin (STZ; 180 mg/kg) injection. 1 week after STZ injection, mice with blood glucose levels higher than 400 mg/dL were used as recipients for transplantation analyses.

Human and mouse islets (200-500 islets or 500-1000 IEQ per animal) or human iPSC-derived insulin-producing cells (i L^(GFP) or i eta cells; 10 million cells per animal) were resuspended in 200 ul RPMI-1640 media. Cells were loaded into laboratory tubing (SiLastic, 508-004) and centrifuged 400 g for 1-2 minutes. Cell clusters were transplanted (approximately 30-50 ul) under kidney capsules in 8-16 week old STZ-injected diabetic mice. Ketamine (80 mg/kg) and Xylazine (10 mg/kg) were used as surgical anesthetics and mice were placed on 37° C. heat pads to recover.

Metabolic Cage Analyses

Metabolic cage analyses were conducted with a Comprehensive Lab Animal Monitoring System (Columbus Instruments). CO₂ production, O₂ consumption, Respiratory Exchange Rate (RER) and ambulatory counts by x-peak were determined for 5 consecutive days and nights, with at least 24 hour adaptation before data recording.

Statistical Methods

Results were expressed as the mean±standard error of the mean (s.e.m.). Statistical comparisons were made using Student's t-test. A statistically significant difference was defined as *P<0.05.

Other Embodiments

From the foregoing description, it will be apparent that variations and modifications may be made to the invention described herein to adopt it to various usages and conditions. Such embodiments are also within the scope of the following claims.

The recitation of a listing of elements in any definition of a variable herein includes definitions of that variable as any single element or combination (or subcombination) of listed elements. The recitation of an embodiment herein includes that embodiment as any single embodiment or in combination with any other embodiments or portions thereof.

All patents and publications mentioned in this specification are herein incorporated by reference to the same extent as if each independent patent and publication was specifically and individually indicated to be incorporated by reference. 

What is claimed is:
 1. An in vitro method for differentiating a pancreatic β-cell progenitor into a mature β-cell comprising the step of: contacting a pancreatic β-cell progenitor cell which expresses PDX1 and insulin with a viral vector encoding estrogen-related receptor γ (ERRγ) in an amount sufficient to overexpress ERRγ in the cell; wherein said contacting differentiates the pancreatic β-cell progenitor cell into a mature β-cell which is capable of glucose-stimulated insulin secretion.
 2. The method of claim 1, wherein the pancreatic β-cell progenitor expresses one or more β cell transcription factors selected from the group consisting of Nkx2.2, NeuroD1, Foxa2, Pax6, HNF4a MafA and Nkx6-1.
 3. The method of claim 1, wherein the pancreatic β-cell progenitor expresses one or more β-cell markers selected from glucagon or somatostatin.
 4. The method of claim 1, wherein the mature pancreatic β-cell expresses one or more mRNA selected from the group consisting of Mafa, Pax6, NeuroD, GCK, CHGA, VAMP2, PC1/3, Glut2, Nkx6.1, GCG, SST, and U36B4. 